Chimeric, hybrid and tandem polypeptides of meningococcal nmb1870

ABSTRACT

NMB1870 is a protein in  Neisseria meningitidis.  Three families of NMB1870 are known. To increase the ability of a NMB1870 protein to elicit antibodies that are cross-reactive between the families, NMB1870 is engineered. Sequences can be substituted from one NMB1870 family into the corresponding position in another family. Proteins of NMB1870 sequences from different families can be joined to each other.

RELATED APPLICATIONS

This application is the U.S. National Phase of International Application No. PCT/IB2006/003876, filed Nov. 27, 2006 and published in English, which claims priority to Great Britain Application No. 0524066.8 filed Nov. 25, 2005. The teachings of the above applications are incorporated in their entirety by reference.

TECHNICAL FIELD

This invention is in the field of immunisation and, in particular, immunisation against diseases caused by pathogenic bacteria in the genus Neisseria, such as N. meningitidis (meningococcus).

BACKGROUND ART

Neisseria meningitidis is a Gram-negative encapsulated bacterium which colonises the upper respiratory tract of approximately 10% of human population. Although polysaccharide and conjugate vaccines are available against serogroups A, C, W135 and Y, this approach cannot be applied to serogroup B because the capsular polysaccharide is a polymer of polysialic acid, which is a self antigen in humans. To develop a vaccine against serogroup B, surface-exposed proteins contained in outer membrane vesicles (OMVs) have been used. These vaccines elicit serum bactericidal antibody responses and protect against disease, but they fail to induce cross-strain protection [1]. Some workers are therefore focusing on specific meningococcal antigens for use in vaccines [2].

One such antigen is ‘NMB1870’. This protein was originally disclosed as protein ‘741’ from strain MC58 [SEQ IDs 2535 & 2536 in ref. 3; SEQ ID 1 herein], and has also been referred to as ‘GNA1870’ [refs. 4-6, following ref. 2] and as ‘ORF2086’ [7-9]. This lipoprotein is expressed across all meningococcal serogroups and has been found in multiple meningococcal strains. NMB1870 sequences have been grouped into three families (referred to herein as families I, II & III), and it has been found that serum raised against a given family is bactericidal within the same family, but is not active against strains which express one of the other two families i.e. there is intra-family cross-protection, but not inter-family cross-protection.

To achieve cross-strain protection using NMB1870, therefore, more than one family is used. To avoid the need to express and purify separate proteins, it has been proposed to express different families as hybrid proteins [10-12], including two or three of the families in a single polypeptide chain. Several hybrids have been tested and give encouraging anti-meningococcal efficacy.

It is an object of the invention to provide further and improved approaches for overcoming the family specificity of protection afforded by NMB1870, and to use these approaches for providing immunity against meningococcal disease and/or infection, particularly for serogroup B.

DISCLOSURE OF THE INVENTION

Complementing the work described in reference 13, the inventors have substituted sequences from one NMB1870 family into the corresponding position in another family, with the aim of producing a chimeric NMB1870 that does not have the family specificity of the wild-type polypeptides.

As an alternative to engineering a single NMB1870 such that it has features of all three families, the inventors have also produced new hybrid and tandem polypeptides that include NMB1870 sequences from multiple families, thereby complementing the work described in references 10 and 12.

Whereas each individual NMB1870 family can elicit antibodies (e.g. in mice) that are effective only against strains in the same NMB1870 family, the chimeric, hybrid and tandem polypeptides of the invention can elicit antibodies that recognise NMB1870 polypeptides from more than one family.

The inventors have also identified various new polymorphic forms of NMB1870, including sequences distinct from the three previously-reported families (family IV).

NMB1870 Family Substitutions

Reference 13 discloses the substitution of sequences from one NMB1870 family into another NMB1870 framework, to give chimeric NMB1870 polypeptides. The inventors have performed further work on chimeras and have identified a number of key residues for substitution in the family NMB1870 sequence. Substitution of these residues can improve the ability of the polypeptide to elicit antibodies that cross-react with family II polypeptides.

Thus the invention provides a polypeptide comprising an amino acid sequence that has at least 70% identity to SEQ ID NO:57, and wherein one or more of the following residues is either substituted with another amino acid or is deleted: F14; T16; Q18; Q20; D21; S22; E23; H24; S25; G26; K27; K31; Q33; R35; 136; G37; 139; K48; E51; G52; R54; T56; A67; G68; K70; T72; A78;A79; N83; K85; D97; D102; P105; G107; R109; S114; S116; L118; N120; Q121; A122; K135; T147; V148; N149; G150; I151; R152; H153.

It is preferred that at least one of the following residues is substituted: F14; T16; Q18; K31; Q33; R35; 136; G37; I39; T56; K70; T72; A78; A79; K85; D97; D102; S114; S116; L118; K135. None of these residues was selected for substitution in reference 13.

Preferred amino acids for substitution or deletion are: F14; T16; Q18; Q20; D21; S22; E23; H24; S25; G26; K27; K31; Q33; R35; 136; G37; K48; E51; G52; R54; T72; A79; K85; P105; G107; R109; L118; N120; Q121; A122; T147; V148; N149; G150; S151; R152; H153. Substitution of residues is preferred, except for E51, where deletion is preferred.

Residues are preferably substituted with the corresponding amino acid from NMB1870 in family II or family III. Preferred substitutions are thus: FI4L; T161; Q18K; Q2ON; D21N; S22P; E23D; H24K; S25I; S25T; G26D; K27S; K31Q; Q33S; R35L; I36V; G37S; I39L; K84Q; G52D; R54K; T56E; A67P; G68N; K70R; T72H; A78T; A79K; N83H; N83Y; K85R; D97E; D102E; P105A; G107E; R109S; S114L; S116D; L118R; N120G; Q121S; A122E; K135R; T1471; V148G; N149E; G150K; I151V; R152H; H153E. Only residues 25 and 83 in this list have more than one preferred substitution, as all of the others have the same amino acid in two of families I, II and III.

The amino acid sequence has at least 70% identity to SEQ ID NO:57, e.g. ≧75%, ≧80%, ≧85%, ≧90%, ≧95%, ≧96%, ≧97%, ≧98%, ≧99% or more. This sequence may be present as part of a larger polypeptide.

The polypeptide can have the ability to induce bactericidal anti-meningococcal antibodies after administration to a host animal, and in preferred embodiments can induce antibodies that are bactericidal against strains in each of the three NMB1870 families I to III. Further information on bactericidal responses is given below.

One preferred amino acid sequence is SEQ ID NO:58 which, compared to SEQ ID NO:57, has substitutions at: F14; T16; Q18; Q20; D21; S22; E23; H24; S25; G26; K27; K31; Q33; R35; I36; G37; K48; G52; R54; T72; A79; N83; K85; P105; G107; R109; L118; N120; Q121; A122; T147; V148; N149; G150; I151; R152; H153. Residue E51 was deleted.

Another substituted sequence is SEQ ID NO:59. Another substituted sequence is SEQ ID NO:60.

Surface Loops for Substitution

Surface loops of SEQ ID NO: 1 have been identified as: (1) amino acids 164-168; (2) amino acids 179-182; (3) amino acids 188-196; (4) amino acids 203-208; (5) amino acids 216-224; (6) amino acids 233-237; (7) amino acids 247-251; and (8) amino acids 262-263:

MNRTAFCCLSLTTALILTACSSGGGGVAADIGAGLADALTAPLDHKDKG LQSLTLDQSVRKNEKLKLAAQGAEKTYGNGDSLNTGKLKNDKVSRFDFI RQIEVDGQLITLESGEFQVYKQSHSALTAFQTEQIQDSEHSGKMVAKRQ FRIGDIAGEHTSFDKLPEGGRATYRGTAFGSDDAGGKLTYTIDFAAKQG NGKIEHLKSPELNVDLAAADIKPDGKRHAVISGSVLYNQAEKGSYSLGI FGGKAQEVAGSAEVKTVNGIRHIGLAAKQ

By aligning SEQ ID NO: 1 with any other NMB1870 sequence, the skilled person can identify the positions of loops (1) to (8) in that sequence. For ease of reference, however, the coordinates of a loop are defined herein as the string of amino acid(s) in a NMB1870 sequence that, when aligned to SEQ ID NO: 1 using a pairwise alignment algorithm, starts with the amino acid aligned to the first amino acid residue of the loop defined above in SEQ ID NO: 1 and ends with the last amino acid of the loop defined above in SEQ ID NO: 1.

Substitution of loop sequences from one family into the loop position in another family allows chimeric NMB1870 to be produced with multi-family antigenicity.

Thus the invention provides a polypeptide comprising a modified amino acid sequence of a first family of NMB1870, wherein the modified sequence includes at least one (e.g. 1, 2, 3, 4, 5, 6 or 7) surface loop sequence from a second family of NMB1870 in place of a surface loop sequence from the first family.

The invention also provides a polypeptide that comprises a backbone sequence in nine parts, with eight loop insertions (one between each consecutive part of backbone sequence), where at least one of the loop sequences is taken from a NMB1870 sequence that is from a different NMB1870 family from the backbone sequence. It is preferred to use surface loops from more than one different NMB1870 sequence, and it is possible to insert these loops into a single backbone sequence. Thus the invention provides a polypeptide comprising an amino acid sequence:

-   -   —B₁-L₁-B₂-L₂-B₃-L₃-B₄-L₄-B₅-L₅-B₆-L₆-B₇-L₇-B₈-L₈-B₉—         wherein:     -   (a) each of said B₁, B₂, B₃, B₄, B₅, B₆, B₇, B₈ and B₉ is: (i) a         fragment of SEQ ID NO: M; or (ii) an amino acid sequence having         at least m % sequence identity to said fragment of (i) and/or         comprising a fragment of at least d contiguous amino acids from         said fragment of (i);     -   (b) each of said L₁, L₂, L₃, L⁴, L₅, L₆, L₇ and L₈ is: (i) a         fragment of SEQ ID NO: 2 and/or of SEQ ID NO: 3; or (ii) an         amino acid sequence having at least n % sequence identity, to         said fragment of (i) and/or comprising a fragment of at least e         contiguous amino acids from said fragment of (i),         provided that at least one of said L₁, L₂, L₃, L₄, L₅, L₆, L₇         and L₈ is not a fragment of SEQ ID NO: M.

The invention also provides a fragment of said polypeptide, provided that the fragment includes at least one of L₁, L₂, L₃, L₄, L₅, L₆, L₇ and/or L₈ and at least one amino acid from two or more of B₁, B₂, B₃, B₄, B₅, B₆, B₇, B₈ and/or B₉. Thus in some embodiments the smallest fragment includes one loop, one amino acid to the N-terminus of that loop and one amino acid to the C-terminus of that loop.

The value of M is selected from 1, 2 or 3, and the definitions of B₁, B₂, B₃, B₄, B₅, B₆, B₇, B₈ and B₉ and of L₁, L₂, L₃, L₄, L₅, L₆, L₇ and L₈ vary depending on the value of M.

The meaning of “(i) a fragment of SEQ ID NO: M” is as follows:

Amino acid co-ordinates within SEQ ID NO: M M B₁ B₂ B₃ B₄ B₅ B₆ B₇ B₈ B₉ 1 1-163 169-178 183-187 197-202 209-215 225-232 238-246 252-261 264-274 2 1-163 168-177 182-186 196-201 208-214 224-231 237-245 251-260 263-273 3 1-171 176-185 190-194 204-209 216-222 232-239 245-253 259-268 271-281

Similarly, “(iii) a fragment of SEQ ID NO: 1, SEQ ID NO: 2 and/or of SEQ ID NO: 3” is defined as:

Amino acid co-ordinates within SEQ ID NO: 1, 2 or 3 SEQ L₁ L₂ L₃ L₄ L₅ L₆ L₇ L₈ 1 164-168 179-182 188-196 203-208 216-224 233-237 247-251 262-263 2 164-167 178-181 187-195 202-207 215-223 232-236 246-250 261-262 3 172-175 186-189 195-203 210-215 223-231 240-244 254-258 269-270

For example, the invention provides a polypeptide comprising an amino acid sequence:

-   -   —B₁-L₁-B₂-L₂-B₃-L₃-B₄-L₄-B₅-L₅-B₅-L₆-B₇-L₇-B₈-L₈-B₉—         wherein: B₁ is amino acids 1-163 of SEQ ID NO: 1, or an amino         acid sequence having at least m % sequence identity to said         amino acids 1-163 and/or comprising a fragment of at least d         contiguous amino acids from said amino acids 1-163; B₂ is amino         acids 169-178 of SEQ ID NO: 1, or an amino acid sequence having         at least m % sequence identity to said amino acids 169-178         and/or comprising a fragment of at least d contiguous amino         acids from said amino acids 169-178 . . . B₉ is amino acids         264-274 of SEQ ID NO: 1, or an amino acid sequence having at         least m % sequence identity to said amino acids 264-274 and/or         comprising a fragment of at least d contiguous amino acids from         said amino acids 264-274; L₁ is amino acids 164-168 of SEQ ID         NO: 2, or an amino acid sequence having at least n % sequence         identity to said amino acids 164-168 and/or comprising a         fragment of at least e contiguous amino acids from said amino         acids 164-168; L₂ is amino acids 179-182 of SEQ ID NO: 2, or an         amino acid sequence having at least n % sequence identity to         said amino acids 179-182 and/or comprising a fragment of at         least e contiguous amino acids from said amino acids 179-182, .         . . L₇ is amino acids 269-270 of SEQ ID NO: 3, or an amino acid         sequence having at least n % sequence identity to said amino         acids 269-270 and/or comprising a fragment of at least e         contiguous amino acids from said amino acids 269-270; etc.

The value of m is selected from 50, 60, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9 or more. The value of n is selected from 50, 60, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9 or more. The value of d is selected from 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 40, 45, 50, 60, 70, 75, 100 or more. The value of e is selected from 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. The value of e is preferably less than 20.

The invention also provides a polypeptide comprising the chimeric amino acid sequence:

-   -   —B₁-L1-B2-L₂-B₃-L₃-B₄-L₄-B₅-L₅-B₆-L₆-B₇-L₇-B₈-L₈-B₉—         as defined above, and further comprising, either N-terminal to         or C-terminal to said chimeric sequence, a NMB1870 sequence,         wherein said NMB1870 sequence is in the same NMB1870 family as         SEQ ID NO: M. Thus the polypeptide comprises both (i) a NMB1870         from a particular family and (ii) also a NMB1870 from the same         family, but with at least one of its surface loops substituted         for a different NMB1870 family.

The invention provides a polypeptide comprising an amino acid sequence that has an overall sequence identity to SEQ ID NO: Q of q %, wherein: the value of q is at least r; the sequence identity of said amino acid sequence to SEQ ID NO: Q is more than q % at the backbone regions of SEQ ID NO: Q; and the sequence identity of said amino acid sequence to SEQ ID NO: Q is less than q % at the loop regions of SEQ ID NO: Q. The value of r is selected from 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97; 98, 99, and 99.5.

The value of Q is 1, 2 or 3, and the boundaries of the loop regions and of the backbone regions are selected accordingly from the above tables (L₁ to L₈ being the loops, and B₁ to B₉ being the backbone).

Where Q is 1, the amino acid sequence in a loop region may have more than q % sequence identity to the corresponding loop region of SEQ ID NO: 2 or SEQ ID NO: 3. Where Q is 2, the amino acid sequence in a loop region may have more than q % sequence identity to the corresponding loop region of SEQ ID NO: 1 or SEQ ID NO: 3. Where Q is 3, the amino acid sequence in a loop region may have more than q % sequence identity to the corresponding loop region of SEQ ID NO: 1 or SEQ ID NO: 2.

Hybrid and Tandem Polypeptides

References 10 to 13 disclose hybrid polypeptides in which a single polypeptide chain includes a NMB1870 sequence and a different meningococcal polypeptide sequence. For instance, hybrids containing NMB1870 and NadA are disclosed in reference 10. Reference 12 discloses a specific subset of hybrid polypeptides, referred to as tandem polypeptides, in which a single polypeptide chain includes multiple NMB1870 sequences e.g. one from each family. The invention provides a number of new hybrid and tandem polypeptides.

In general, a hybrid polypeptide can be represented by the formula:

-A-[-X-L-_(n)-B—

wherein X is an amino acid sequence comprising a Neisserial sequence, L is an optional linker amino acid sequence, A is an optional N-terminal amino acid sequence, B is an optional C-terminal amino acid sequence, and n is an integer greater than 1.

The value of n can be 2, 3, 4, 5, 6, 7, 8 or more, but is preferably 2 or 3. The -A- sequence is preferably at the N-terminus of the polypeptide, and the —B— sequence is preferably at the C-terminus of the polypeptide.

According to the invention, at least one of the —X— moieties is a NMB1870 sequence. Preferred NMB1870 sequences for use as —X— moieties are truncated up to and including the poly-glycine sequence found near the mature N-terminus i.e. they are ΔG sequences. The ΔG versions of SEQ ID NOs: 1 to 3 are SEQ ID NOs: 22 to 24, respectively.

For X moieties, particularly those other than X₁, it is preferred that the native leader peptide should be omitted. In one embodiment, the leader peptides will be deleted except for that of the —X— moiety located at the N-terminus of the hybrid polypeptide i.e. the leader peptide of X₁ will be retained, but the leader peptides of X₂ . . . X_(n) will be omitted. This is equivalent to deleting all leader peptides and using the leader peptide of X₁ as moiety -A-.

For each n instances of [—X-L-], linker amino acid sequence -L- may be present or absent. For instance, when n=2 the hybrid may be NH₂—X₁-L₁-X₂-L₂-COOH, NH₂—X₁—X₂—COOH, NH₂—X₁-L₁-X₂—COOH, NH₂—X₁—X₂-L₂-COOH, etc. Linker amino acid sequence(s) -L- will typically be short (e.g. 20 or fewer amino acids i.e. 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1). Examples include short peptide sequences which facilitate cloning, poly-glycine linkers (i.e. Gly_(n) where n=2, 3, 4, 5, 6, 7, 8, 9, 10 or more), and histidine tags (i.e. His_(n) where n=3, 4, 5, 6, 7, 8, 9, 10 or more). Other suitable linker amino acid sequences will be apparent to those skilled in the art. A useful linker is GSGGGG (SEQ ID NO: 15), with the Gly-Ser dipeptide being formed from a BamHI restriction site, thus aiding cloning and manipulation, and the Gly₄ tetrapeptide (SEQ ID NO: 16) is another typical poly-glycine linker. Another useful linker is SEQ ID NO: 17, which can optionally be preceded by a Gly-Ser dipeptide (SEQ ID NO: 18, from BamHI) or a Gly-Lys dipeptide (SEQ ID NO: 19, from HindIII)

-A- is an optional N-terminal amino acid sequence. This will typically be short (e.g. 40 or fewer amino acids i.e. 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1). Examples include leader sequences to direct protein trafficking, or short peptide sequences which facilitate cloning or purification (e.g. histidine tags i.e. His_(n) where n=3, 4, 5, 6, 7, 8, 9, 10 or more). Other suitable N-terminal amino acid sequences will be apparent to those skilled in the art. If X1 lacks its own N-terminus methionine, -A- may provide such a methionine residue in the translated polypeptide (e.g. -A- is a single Met residue). The Met may be to the N-terminus of a linker sequence such as SEQ ID NO: 17 (i.e. SEQ ID: 21), or at the N-terminus of a short sequence (e.g. SEQ ID NO: 26). Examples of -A- sequences include SEQ ID NOs: 21, 26 and 43.

—B— is an optional C-terminal amino acid sequence. This will typically be short (e.g. 40 or fewer amino acids i.e. 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1). Examples include sequences to direct protein trafficking, short peptide sequences which facilitate cloning or purification (e.g. comprising histidine tags i.e. His_(n) where n=3, 4, 5, 6, 7, 8, 9, 10 or more e.g. SEQ ID NO: 20), or sequences which enhance polypeptide stability. Other suitable C-terminal amino acid sequences will be apparent to those skilled in the art. One suitable —B— moiety is SEQ ID NO: 41, in which the Leu-Glu (SEQ ID NO: 44) upstream of SEQ ID NO: 20 arises from a XhoI restriction site.

In preferred hybrid polypeptides of the invention, one of the X moieties is a ‘protein 936’ sequence. Protein 936 was originally disclosed as SEQ ID NO 2884 in ref. 3 (SEQ ID NO: 14 herein), and a signal-truncated version of this sequence is SEQ ID NO: 25 herein. ‘936’ sequences for use with the invention include sequences (i) having at least z % sequence identity to SEQ ID NO: 25, and/or (ii) comprising a fragment of at least f contiguous amino acids from SEQ ID NO: 25. The value of z is selected from 50, 60, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9 or more. The value of f is selected from 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 40, 45, 50, 60, 70, 75, 100, 150, 200 or more.

Some preferred hybrid polypeptides include a 936 sequence and two NMB1870 sequences. The two NMB1870 sequences will be from two different families e.g. I & II, I & III, or II & III. Preferred hybrids include a 936 sequence, a family I NMB1870 sequence and a family H NMB1870 sequence. The 936 is preferably the most N-terminal of these three sequences. SEQ ID NOs: 28, 29, 34 & 35 are examples of hybrid polypeptides including a 936 sequence to the N-terminus of NMB1870 sequences from two different families.

For example, where n=2 then X₁ may be a ‘936’ sequence and X₂ may be a NMB1870 sequence. Similarly, where n=3 then X₁ may be a ‘936’ sequence and X₂ may be a NMB1870 sequence from a first family, and X₂ may be a NMB1870 sequence from a second family.

In preferred tandem polypeptides of the invention n is 2 or 3.

Fourteen specific hybrid and tandem polypeptides of the invention are disclosed as SEQ ID NOs: 27 to 40 which, for guidance, are built up from SEQ ID NOs as follows:

SEQ ID n A X₁ L₁ X₂ L₂ X₃ L₃ B 27 2 21 23 15 22 44 — — 20 28 3 26 25 15 22 18 23 44 20 29 3 26 25 18 23 45 22 44 20 30 3 21 23 15 22 18 24 42 20 31 3 21 23 18 24 15 22 44 20 32 3 43 22 18 23 18 24 42 20 33 2 21 23 15 22 — — — — 34 3 26 25 15 22 18 23 — — 35 3 26 25 18 23 15 22 — — 36 3 21 23 18 24 15 22 — — 37 3 21 23 15 22 18 24 — — 38 3 43 22 18 23 18 24 — — 39 3 43 22 18 24 19 23 44 20 40 3 43 22 18 24 19 23 — —

Further preferred hybrid and tandem polypeptides of the invention include a family IV sequence. Thus at least one X moiety may (i) have at least v % sequence identity to SEQ ID NO: 95, and/or (ii) comprise a fragment of at least vv contiguous amino acids from SEQ ID NO: 95. The value of v is selected from 50, 60, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9 or more. The value of vv is selected from 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 40, 45, 50, 60, 70, 75, 100, 150, 200 or more. By including a family IV sequence, serum activity against 269 cpx strains can be improved.

Fragments and Domains of NMB1870

Rather than use a full-length NMB1870 sequence (e.g. SEQ ID NO: 1), the invention will typically use a fragment. For instance, the amino acids upstream of the mature N-terminus (Cys-20 in SEQ ID NO: 1) will generally be omitted. Preferably, a “ΔG” sequence will be used, in which all of the amino acids up to and including NMB1870's poly-glycine sequence are deleted i.e. deletion of amino acids 1-26 in SEQ ID NO: 1. In SEQ ID NOs: 27 to 40, for instance, the above table shows that ΔG forms of NMB1870 (i.e. SEQ ID NOs: 22 to 24) are used.

As disclosed in reference 13, NMB1870 can be split into three domains, referred to as A, B and C. Taking the family I sequence (SEQ ID NO: 1), in which the N-terminus of the mature processed lipoprotein is Cys-20, the three domains are (A) 1-119, (B) 120-183 and (C) 184-274:

MNRTAFCCLSLTTALILTACSSGGGGVAADIGAGLADALTAPLDHKDKG LQSLTLDQSVRKNEKLKLAAQGAEKTYGNGDSLNTGKLKNDKVSRFDFI RQIEVDGQLITLESGEFQVYKQSHSALTAFQTEQIQDSEHSGKMVAKRQ FRIGDIAGEHTSFDKLPEGGRATYRGTAFGSDDAGGKLTYTIDFAAKQG NGKIEHLKSPELNVDLAAADIKPDGKRHAVISGSVLYNQAEKGSYSLGI FGGKAQEVAGSAEVKTVNGIRHIGLAAKQ

The mature form of domain ‘A’, from its C-terminus cysteine, is called ‘A_(mature)’.

For MC58, the domains are: ‘A’=SEQ ID NO: 4; ‘B’=SEQ ID NO: 5;=SEQ ID NO: 6; and ‘A_(mature)’=SEQ ID NO: 13. Multiple NMB1870 sequences are known [e.g. see refs. 4, 8 and 10] and can readily be aligned using standard methods. By such alignments the skilled person can identify domains ‘A’ (and ‘A_(mature)’), ‘B’ and in any given NMB1870 sequence by comparison to the coordinates in the MC58 sequence. For ease of reference, however, the domains are defined below:

-   -   Domain ‘A’ in a given NMB1870 sequence is the fragment of that         sequence which, when aligned to SEQ ID NO: 1 using a pairwise         alignment algorithm, starts with the amino acid aligned to Met-1         of SEQ ID NO: 1 and ends with the amino acid aligned to Lys-119         of SEQ ID NO: 1.     -   Domain ‘A_(mature)’ in a given NMB1870 sequence is the fragment         of that sequence which, when aligned to SEQ ID NO: 1 using a         pairwise alignment algorithm, starts with the amino acid aligned         to Cys-20 of SEQ ID NO: 1 and ends with the amino acid aligned         to Lys-119 of SEQ ID NO: 1.     -   Domain ‘B’ in a given NMB1870 sequence is the fragment of that         sequence which, when aligned to SEQ ID NO: 1 using a pairwise         alignment algorithm, starts with the amino acid aligned to         Gln-120 of SEQ ID NO: 1 and ends with the amino acid aligned to         Gly-183 of SEQ ID NO: 1.     -   Domain ‘C’ in a given NMB1870 sequence is the fragment of that         sequence which, when aligned to SEQ ID NO: 1 using a pairwise         alignment algorithm, starts with the amino acid aligned to         Lys-184 of SEQ ID NO: 1 and ends with the amino acid aligned to         Gln-274 of SEQ ID NO 1.

The preferred pairwise alignment algorithm for defining the domains is the Needleman-Wunsch global alignment algorithm [14], using default parameters (e.g. with Gap opening penalty=10.0, and with Gap extension penalty=0.5, using the EBLOSUM62 scoring matrix). This algorithm is conveniently implemented in the needle tool in the EMBOSS package [15].

NMB1870 sequences fall into three families [4,10] that are referred to herein as families I, II and III. The prototypic sequences for families I-III are, respectively, SEQ ID NOS: 1-3. The phylogenetic and dendrogram methods of reference 4 can be followed in order to readily determine the family for any given NMB1870 sequence, and a pairwise alignment with each of the three prototypic NMB1870 sequences can also be used to find the closest family match. Sequences fall distinctly into the three families, with sequence identity being 74.1% between families I & II, 62.8% between families I & III and 84.7% between families II & III, and with sequence variation within each family being low (e.g. a minimum of 91.6% identity in family I, 93.4% in family II and 93.2% in family III). As a quick way of determining a sequence's family without requiring a phylogenetic analysis, a sequence can be placed in family I if it has at least 85% sequence identity to SEQ ID NO: 1, can be placed in family II if it has at least 85% sequence identity to SEQ ID NO: 2, and can be placed in family III if it has at least 85% sequence identity to SEQ ID NO: 3.

Based on the alignment in FIG. 6 of reference 4, exemplary domains A, B and C for the three prototypic families of NMB1870 (SEQ ID NOS: 1 to 3) are as follows:

↓Family Domain→ A B C I SEQ ID NO: 4 SEQ ID NO: 5 SEQ ID NO: 6 II SEQ ID NO: 7 SEQ ID NO: 8 SEQ ID NO: 9 III SEQ ID NO: 10 SEQ ID NO: 11 SEQ ID NO: 12

Preferred domains for use with the invention comprise amino acid sequences that (a) have at least x % sequence identity to one or more of SEQ ID NOS: 4 to 12, and/or (a) comprise a fragment of at least y consecutive amino acids sequence from one or more of SEQ ID NOS: 4 to 12.

The value of x is selected from 50, 60, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9 or more. The value of y is selected from 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 35, 40, 45, 50 or more. In polypeptides comprising NMB1870 sequences from different families, the values of x and y for each family can be the same or different.

A domain ‘A’ sequence is preferably between a₁ and a₂ (inclusive) amino acids long, where: a₁ is selected from 110, 115, 120, 125 and 130; and a₂ is selected from 115, 120, 125, 130 and 135.

A domain ‘B’ sequence is preferably between b₁ and b₂ (inclusive) amino acids long, where: b₁ is selected from 55, 60, 65 and 70; and b₂ is selected from 60, 65, 70 and 75.

A domain ‘C’ sequence is preferably between c₁ and c₂ (inclusive) amino acids long, where: c₁ is selected from 80, 85, 90, 95 and 100; and c₂ is selected from 85, 90, 95, 100 and 105.

As desired, any full-length form of NMB1870 can be replaced by a single NMB1870 domain (A, B or C) or by two NMB1870 domains (AB, AC or BC).

Polymorphic Forms of NMB1870

Various polymorphic forms of NMB1870 have previously been reported. New sequences have been identified, and so the invention provides a polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 86, 87, 88, 89, 90, 91, 92, 93 and 94. SEQ ID NO: 94 (see also SEQ ID NO: 140 of ref. 12) is an example of a family IV sequence, which may have arisen by recombination between families I and III.

Polypeptides

The invention provides the polypeptides various described above.

It also provides a polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55 and 56. It also provides polypeptides having an amino acid sequence (a) having sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NOS: 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55 and 56 and/or (b) comprising a fragment of an amino acid sequence selected from the group consisting of SEQ ID NOS: 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55 and 56. The degree of sequence identity is preferably greater than 50% (e.g. 60%, 70%, 80%, 90%, 95%, 99% or more). The fragment preferably comprises 7 or more consecutive amino acids from the starting sequence (e.g. 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 45, 50, 55, 60, 65, 70, 75, 70, 85, 90, 95, 100 or more).

NMB1870 is naturally a lipoprotein in N. meningitidis. It has also been found to be lipidated when expressed in E. coli. Polypeptides of the invention may have a C-terminus cysteine residue, which may be lipidated e.g. comprising a palmitoyl group.

A characteristic of preferred polypeptides of the invention is the ability to induce bactericidal anti-meningococcal antibodies after administration to a host animal.

Polypeptides of the invention can be prepared by various means e.g. by chemical synthesis (at least in part), by digesting longer polypeptides using proteases, by translation from RNA, by purification from cell culture (e.g. from recombinant expression or from N. meningitidis culture). etc.

Heterologous expression in an E. coli host is a preferred expression route (e.g. in DH5α, BL21(DE₃), BLR, etc.).

Polypeptides of the invention may be attached or immobilised to a solid support.

Polypeptides of the invention may comprise a detectable label e.g. a radioactive label, a fluorescent label, or a biotin label. This is particularly useful in immunoassay techniques.

Polypeptides can take various forms (e.g. native, fusions, glycosylated, non-glycosylated, lipidated, disulfide bridges, etc.).

Polypeptides are preferably prepared in substantially pure or substantially isolated form (i.e. substantially free from other Neisserial or host cell polypeptides) or substantially isolated form. In general, the polypeptides are provided in a non-naturally occurring environment e.g. they are separated from their naturally-occurring environment. In certain embodiments, the subject polypeptide is present in a composition that is enriched for the polypeptide as compared to a control. As such, purified polypeptide is provided, whereby purified is meant that the polypeptide is present in a composition that is substantially free of other expressed polypeptides, where by substantially free is meant that less than 90%, usually less than 60% and more usually less than 50% of the composition is made up of other expressed polypeptides.

The term “polypeptide” refers to amino acid polymers of any length. The polymer may be linear or branched, it may comprise modified amino acids, and it may be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified naturally or by intervention; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation or modification, such as conjugation with a labeling component. Also included within the definition are, for example, polypeptides containing one or more analogs of an amino acid (including, for example, unnatural amino acids, etc.), as well as other modifications known in the art. Polypeptides can occur as single chains or associated chains.

Nucleic Acids

The invention provides nucleic acid encoding a polypeptide of the invention as defined above. The invention also provides nucleic acid comprising: (a) a fragment of at least n consecutive nucleotides from said nucleic acid, wherein n is 10 or more (e.g. 12, 14, 15, 18, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100, 150, 200, 500 or more); and/or (b) a sequence having at least 50% (e.g. 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99% or more) sequence identity to said nucleic acid.

Furthermore, the invention provides nucleic acid which can hybridise to nucleic acid encoding a polypeptide of the invention, preferably under “high stringency” conditions (e.g. 65° C. in a 0.1×SSC, 0.5% SDS solution).

Nucleic acids of the invention can be used in hybridisation reactions (e.g. Northern or Southern blots, or in nucleic acid microarrays or ‘gene chips’) and amplification reactions (e.g. PCR, SDA, SSSR, LCR, TMA, NASBA, etc.) and other nucleic acid techniques.

Nucleic acids of the invention may be prepared in many ways e.g. by chemical synthesis (e.g. phosphoramidite synthesis of DNA) in whole or in part, by digesting longer nucleic acids using nucleases (e.g. restriction enzymes), by joining shorter nucleic acids or nucleotides (e.g. using ligases or polymerases), from genomic or cDNA libraries, etc.

Nucleic acids of the invention can take various forms e.g. single-stranded, double-stranded, vectors, primers, probes, labelled, unlabelled, etc.

Nucleic acids of the invention are preferably in isolated or substantially isolated form.

The invention includes nucleic acid comprising sequences complementary to those described above e.g. for antisense or probing, or for use as primers.

The term “nucleic acid” includes DNA and RNA, and also their analogues, such as those containing modified backbones, and also peptide nucleic acids (PNA), etc.

Nucleic acid according to the invention may be labelled e.g. with a radioactive or fluorescent label. This is particularly useful where the nucleic acid is to be used in nucleic acid detection techniques e.g. where the nucleic acid is a primer or as a probe for use in techniques such as PCR, LCR, TMA, NASBA, etc.

The invention also provides vectors comprising nucleotide sequences of the invention (e.g. cloning or expression vectors, such as those suitable for nucleic acid immunisation) and host cells transformed with such vectors.

Bactericidal Responses

Preferred polypeptides of the invention can elicit antibody responses that are bactericidal against meningococci. Bactericidal antibody responses are conveniently measured in mice and are a standard indicator of vaccine efficacy [e.g. see end-note 14 of reference 2]. Polypeptides of the invention can preferably elicit an antibody response which is bactericidal against at least one N. meningitidis strain from each of at least two of the following three groups of strains:

-   -   (I) MC58, gb185 (=M01-240185), m4030, m2197, m2937, iss1001,         NZ394/98, 67/00, 93/114, bz198, m1390, nge28, 1np17592,         00-241341, f6124, 205900, m198/172, bz133, gb149 (=M01-240149),         nm008, nm092, 30/00, 39/99, 72/00, 95330, bz169, bz83, cu385,         h44/76, m1590, m2934, m2969, m3370, m4215, m4318, n44/89, 14847.     -   (II) 961-5945, 2996, 96217, 312294, 11327, a22, gb013         (=M01-240013), e32, m1090, m4287, 860800, 599, 95N477, 90-18311,         c11, m986, m2671, 1000, m1096, m3279, bz232, dk353, m3697,         ngh38, L93/4286.     -   (III) M1239, 16889, gb355 (=M01-240355), m3369, m3813, ngp165.

For example, a chimeric polypeptide can elicit a bactericidal response effective against two or more of serogroup B N. meningitidis strains MC58, 961-5945 and M1239.

The polypeptide can preferably elicit an antibody response which is bactericidal against at least 50% of clinically-relevant meningococcal serogroup B strains (e.g. 60%, 70%, 80%, 90%, 95% or more). The polypeptide may elicit an antibody response which is bactericidal against strains of serogroup B N. meningitidis and strains of at least one (e.g. 1, 2, 3, 4) of serogroups A, C, W135 and Y. The polypeptide may elicit an antibody response which is bactericidal against strains of N. gonococcus and/or N. cinerea. The polypeptide may elicit a response which is bactericidal against strains from at least two of the three main branches of the dendrogram shown in FIG. 5 of reference 4.

The polypeptide may elicit an antibody response which is bactericidal against N. meningitidis strains in at least 2 (e.g. 2, 3, 4, 5, 6, 7) of hypervirulent lineages ET-37, ET-5, cluster A4, lineage 3, subgroup I, subgroup III, and subgroup IV-1 [16,17]. Polypeptides may additionally induce bactericidal antibody responses against one or more hyperinvasive lineages.

Polypeptides may elicit an antibody response which is bactericidal against N. meningitidis strains in at least at least 2 (e.g. 2, 3, 4, 5, 6, 7) of the following multilocus sequence types: ST1, ST4, ST5, ST8, ST11, ST32 and ST41 [18]. The polypeptide may also elicit an antibody response which is bactericidal against ST44 strains.

The polypeptide need not induce bactericidal antibodies against each and every MenB strain within the specified lineages or MLST; rather; for any given group of four of more strains of serogroup B meningococcus within a particular hypervirulent lineage or MLST, the antibodies induced by the composition are preferably bactericidal against at least 50% (e.g. 60%, 70%, 80%, 90% or more) of the group. Preferred groups of strains will include strains isolated in at least four of the following countries: GB, AU, CA, NO, IT, US, NZ, NL, BR, and CU. The serum preferably has a bactericidal titre of at least 1024 (e.g. 2¹⁰, 2¹¹, 2¹², 2¹³, 2¹⁴, 2¹⁵, 2¹⁶, 2¹⁷, 2¹⁸ or higher, preferably at least 2¹⁴) i.e. the serum is able to kill at least 50% of test bacteria of a particular strain when diluted 1:1024 e.g. as described in end-note 14 of reference 2. Preferred chimeric polypeptides can elicit an antibody response in mice that remains bactericidal even when the serum is diluted 1:4096 or further.

Immunisation

Polypeptides of the invention are preferably provided as immunogenic compositions, and the invention provides an immunogenic composition of the invention for use as a medicament.

The invention also provides a method for raising an antibody response in a mammal, comprising administering an immunogenic composition of the invention to the mammal. The antibody response is preferably a protective and/or bactericidal antibody response.

The invention also provides a method for protecting a mammal against a Neisserial (e.g. meningococcal) infection, comprising administering to the mammal an immunogenic composition of the invention.

The invention provides chimeric polypeptides of the invention for use as medicaments (e.g. as immunogenic compositions or as vaccines) or as diagnostic reagents. It also provides the use of nucleic acid, polypeptide, or antibody of the invention in the manufacture of a medicament for preventing Neisserial (e.g. meningococcal) infection in a mammal.

The mammal is preferably a human. The human may be an adult or, preferably, a child. Where the vaccine is for prophylactic use, the human is preferably a child (e.g. a toddler or infant); where the vaccine is for therapeutic use, the human is preferably an adult. A vaccine intended for children may also be administered to adults e.g. to assess safety, dosage, immunogenicity, etc.

The uses and methods are particularly useful for preventing/treating diseases including, but not limited to, meningitis (particularly bacterial meningitis) and bacteremia.

Efficacy of therapeutic treatment can be tested by monitoring Neisserial infection after administration of the composition of the invention. Efficacy of prophylactic treatment can be tested by monitoring immune responses against NMB1870 after administration of the composition. Immunogenicity of compositions of the invention can be determined by administering them to test subjects (e.g. children 12-16 months age, or animal models [19]) and then determining standard parameters including serum bactericidal antibodies (SBA) and ELISA titres (GMT). These immune responses will generally be determined around 4 weeks after administration of the composition, and compared to values determined before administration of the composition. A SBA increase of at least 4-fold or 8-fold is preferred. Where more than one dose of the composition is administered, more than one post-administration determination may be made.

Preferred compositions of the invention can confer an antibody titre in a patient that is superior to the criterion for seroprotection for each antigenic component for an acceptable percentage of human subjects. Antigens with an associated antibody titre above which a host is considered to be seroconverted against the antigen are well known, and such titres are published by organisations such as WHO. Preferably more than 80% of a statistically significant sample of subjects is seroconverted, more preferably more than 90%, still more preferably more than 93% and most preferably 96-100%.

Compositions of the invention will generally be administered directly to a patient. Direct delivery may be accomplished by parenteral injection (e.g. subcutaneously, intraperitoneally, intravenously, intramuscularly, or to the interstitial space of a tissue), or by rectal, oral, vaginal, topical, transdermal, intranasal, ocular, aural, pulmonary or other mucosal administration. Intramuscular administration to the thigh or the upper arm is preferred. Injection may be via a needle (e.g. a hypodermic needle), but needle-free injection may alternatively be used. A typical intramuscular dose is about 0.5 ml.

The invention may be used to elicit systemic and/or mucosal immunity.

Dosage treatment can be a single dose schedule or a multiple dose schedule. Multiple doses may be used in a primary immunisation schedule and/or in a booster immunisation schedule. A primary dose schedule may be followed by a booster dose schedule. Suitable timing between priming doses (e.g. between 4-16 weeks), and between priming and boosting, can be routinely determined.

The immunogenic composition of the invention will generally, include a pharmaceutically acceptable carrier, which can be any substance that does not itself induce the production of antibodies harmful to the patient receiving the composition, and which can be administered without undue toxicity. Pharmaceutically acceptable carriers can include liquids such as water, saline, glycerol and ethanol. Auxiliary substances, such as wetting or emulsifying agents, pH buffering substances, and the like, can also be present in such vehicles. A thorough discussion of suitable carriers is available in ref. 20.

Neisserial infections affect various areas of the body and so the compositions of the invention may be prepared in various forms. For example, the compositions may be prepared as injectables, either as liquid solutions or suspensions. Solid forms suitable for solution in, or suspension in, liquid vehicles prior to injection can also be prepared. The composition may be prepared for topical administration e.g. as an ointment, cream or powder. The composition be prepared for oral administration e.g. as a tablet or capsule, or as a syrup (optionally flavoured). The composition may be prepared for pulmonary administration e.g. as an inhaler, using a fine powder or a spray. The composition may be prepared as a suppository or pessary. The composition may be prepared for nasal, aural or ocular administration e.g. as drops.

The composition is preferably sterile. It is preferably pyrogen-free. It is preferably buffered e.g. at between pH 6 and pH 8, generally around pH 7. Where a composition comprises an aluminium hydroxide salt, it is preferred to use a histidine buffer [21]. Compositions of the invention may be isotonic with respect to humans.

Immunogenic compositions comprise an immunologically effective amount of immunogen, as well as any other of other specified components, as needed. By ‘immunologically effective amount’, it is meant that the administration of that amount to an individual, either in a single dose or as part of a series, is effective for treatment or prevention. This amount varies depending upon the health and physical condition of the individual to be treated, age, the taxonomic group of individual to be treated (e.g. non-human primate, primate, etc.), the capacity of the individual's immune system to synthesise antibodies, the degree of protection desired, the formulation of the vaccine, the treating doctor's assessment of the medical situation, and other relevant factors. It is expected that the amount will fall in a relatively broad range that can be determined through routine trials. Dosage treatment may be a single dose schedule or a multiple dose schedule (e.g. including booster doses). The composition may be administered in conjunction with other immunoregulatory agents.

Adjuvants which may be used in compositions of the invention include, but are not limited to:

A. Mineral-Containing Compositions

Mineral containing compositions suitable for use as adjuvants in the invention include mineral salts, such as aluminium salts and calcium salts. The invention includes mineral salts such as hydroxides (e.g. oxyhydroxides), phosphates (e.g. hydroxyphosphates, orthophosphates), sulphates, etc. [e.g. see chapters 8 & 9 of ref. 22], or mixtures of different mineral compounds, with the compounds taking any suitable form (e.g. gel, crystalline, amorphous, etc.), and with adsorption being preferred. The mineral containing compositions may also be formulated as a particle of metal salt [23].

Aluminium phosphates are particularly preferred, particularly in compositions which include a H. influenzae saccharide antigen, and a typical adjuvant is amorphous aluminium hydroxyphosphate with PO₄/Al molar ratio between 0.84 and 0.92, included at 0.6mg Al³⁺/ml. Adsorption with a low dose of aluminium phosphate may be used e.g. between 50 and 100 μg Al³⁺ per conjugate per dose. Where there is more than one conjugate in a composition, not all conjugates need to be adsorbed.

B. Oil Emulsions

Oil emulsion compositions suitable for use as adjuvants in the invention include squalene-water emulsions, such as MF59 [Chapter 10 of ref. 22; see also ref. 24] (5% Squalene, 0.5% Tween 80, and 0.5% Span 85, formulated into submicron particles using a microfluidizer). Complete Freund's adjuvant (CFA) and incomplete Freund's adjuvant (IFA) may also be used. Oil-in-water emulsions adjuvants are useful with the invention.

C. Saponin Formulations [Chapter 22 of Ref. 22]

Saponin formulations may also be used as adjuvants in the invention. Saponins are a heterologous group of sterol glycosides and triterpenoid glycosides that are found in the bark, leaves, stems, roots and even flowers of a wide range of plant species. Saponin from the bark of the Quillaia saponaria Molina tree have been widely studied as adjuvants. Saponin can also be commercially obtained from Smilax ornata (sarsaprilla), Gypsophilla paniculata (brides veil), and Saponaria officianalis (soap root). Saponin adjuvant formulations include purified formulations, such as QS21, as well as lipid formulations, such as ISCOMs. QS21 is marketed as Stimulon™.

Saponin compositions have been purified using HPLC and RP-HPLC. Specific purified fractions using these techniques have been identified, including QS7, QS17, QS18, QS21, QH-A, QH-B and QH-C. Preferably, the saponin is QS21. A method of production of QS21 is disclosed in ref. 25. Saponin formulations may also comprise a sterol, such as cholesterol [26].

Combinations of saponins and cholesterols can be used to form unique particles called immunostimulating complexs (ISCOMs) [chapter 23 of ref. 22]. ISCOMs typically also include a phospholipid such as phosphatidylethanolamine or phosphatidylcholine. Any known saponin can be used in ISCOMs. Preferably, the ISCOM includes one or more of QuilA, QHA & QHC. ISCOMs are further described in refs. 26-28. Optionally, the ISCOMS may be devoid of additional detergent [29].

A review of the development of saponin based adjuvants can be found in refs. 30 & 31.

D. Virosomes and Virus-Like Particles

Virosomes and virus-like particles (VLPs) can also be used as adjuvants in the invention. These structures generally contain one or more proteins from a virus optionally combined or formulated with a phospholipid. They are generally non-pathogenic, non-replicating and generally do not contain any of the native viral genome. The viral proteins may be recombinantly produced or isolated from whole viruses. These viral proteins suitable for use in virosomes or VLPs include proteins derived from influenza virus (such as HA or NA), Hepatitis B virus (such as core or capsid proteins), Hepatitis E virus, measles virus, Sindbis virus, Rotavirus, Foot-and-Mouth Disease virus, Retrovirus, Norwalk virus, human Papilloma virus, HIV, RNA-phages, Qβ-phage (such as coat proteins), GA-phage, fr-phage, AP205 phage, and Ty (such as retrotransposon Ty protein p 1). VLPs are discussed further in refs. 32-37. Virosomes are discussed further in, for example, ref. 38

E. Bacterial or Microbial Derivatives

Adjuvants suitable for use in the invention include bacterial or microbial derivatives such as non-toxic derivatives of enterobacterial lipopolysaccharide (LPS), Lipid A derivatives, immunostimulatory oligonucleotides and ADP-ribosylating toxins and detoxified derivatives thereof.

Non-toxic derivatives of LPS include monophosphoryl lipid A (MPL) and 3-O-deacylated MPL (3dMPL). 3dMPL is a mixture of 3 de-O-acylated monophosphoryl lipid A with 4, 5 or 6 acylated chains. A preferred “small particle” form of 3 De-O-acylated monophosphoryl lipid A is disclosed in ref. 39. Such “small particles” of 3dMPL are small enough to be sterile filtered through a 0.22 μm membrane [39]. Other non-toxic LPS derivatives include monophosphoryl lipid A mimics, such as aminoalkyl glucosaminide phosphate derivatives e.g. RC-529 [40,41].

Lipid A derivatives include derivatives of lipid A from Escherichia coli such as 0M-174. OM-174 is described for example in refs. 42 & 43.

Immunostimulatory oligonucleotides suitable for use as adjuvants in the invention include nucleotide sequences containing a CpG motif (a dinucleotide sequence containing an unmethylated cytosine linked by a phosphate bond to a guanosine). Double-stranded RNAs and oligonucleotides containing palindromic or poly(dG) sequences have also been shown to be immunostimulatory.

The CpG's can include nucleotide modifications/analogs such as phosphorothioate modifications and can be double-stranded or single-stranded. References 44, 45 and 46 disclose possible analog substitutions e.g. replacement of guanosine with 2′-deoxy-7-deazaguanosine. The adjuvant effect of CpG oligonucleotides is further discussed in refs. 47-52.

The CpG sequence may be directed to TLR9, such as the motif GTCGTT or TTCGTT [53]. The CpG sequence may be specific for inducing a Th1 immune response, such as a CpG-A ODN, or it may be more specific for inducing a B cell response, such a CpG-B ODN. CpG-A and CpG-B ODNs are discussed in refs. 54-56. Preferably, the CpG is a CpG-A ODN.

Preferably, the CpG oligonucleotide is constructed so that the 5′ end is accessible for receptor recognition. Optionally, two CpG oligonucleotide sequences may be attached at their 3′ ends to form “immunomers”. See, for example, refs. 53 & 57-59.

Bacterial ADP-ribosylating toxins and detoxified derivatives thereof may be used as adjuvants in the invention. Preferably, the protein is derived from E. coli (E. coli heat labile enterotoxin “LT”), cholera (“CT”), or pertussis (“PT”). The use of detoxified ADP-ribosylating toxins as mucosal adjuvants is described in ref. 60 and as parenteral adjuvants in ref. 61. The toxin or toxoid is preferably in the form of a holotoxin, comprising both A and B subunits. Preferably, the A subunit contains a detoxifying mutation; preferably the B subunit is not mutated. Preferably, the adjuvant is a detoxified LT mutant such as LT-K63, LT-R72, and LT-G192. The use of ADP-ribosylating toxins and detoxified derivaties thereof, particularly LT-K63 and LT-R72, as adjuvants can be found in refs. 62-69. Numerical reference for amino acid substitutions is preferably based on the alignments of the A and B subunits of ADP-ribosylating toxins set forth in ref. 70, specifically incorporated herein by reference in its entirety.

F. Human Immunomodulators

Human immunomodulators suitable for use as adjuvants in the invention include cytokines, such as interleukins (e.g. IL-1, IL-2, IL-4, IL-5, IL-6, IL-7, IL-12 [71], etc.) [72], interferons (e.g. interferon-γ), macrophage colony stimulating factor, and tumor necrosis factor.

G. Bioadhesives and Mucoadhesives

Bioadhesives and mucoadhesives may also be used as adjuvants in the invention. Suitable bioadhesives include esterified hyaluronic acid microspheres [73] or mucoadhesives such as cross-linked derivatives of poly(acrylic acid), polyvinyl alcohol, polyvinyl pyrollidone, polysaccharides and carboxymethylcellulose. Chitosan and derivatives thereof may also be used as adjuvants in the invention [74).

H. Microparticles

Microparticles may also be used as adjuvants in the invention. Microparticles (i.e. a particle of ˜100 nm to ˜150 μm in diameter, more preferably ˜200 nm to ˜30 μm in diameter, and most preferably ˜500 nm to ˜10 μm in diameter) formed from materials that are biodegradable and non-toxic (e.g. a poly(a-hydroxy acid), a polyhydroxybutyric acid, a polyorthoester, a polyanhydride, a polycaprolactone, etc.), with poly(lactide-co-glycolide) are preferred, optionally treated to have a negatively-charged surface (e.g. with SDS) or a positively-charged surface (e.g. with a cationic detergent, such as CTAB).

I. Liposomes (Chapters 13 & 14 of Ref. 22)

Examples of liposome formulations suitable for use as adjuvants are described in refs. 75-77.

J. Polyoxyethylene Ether and Polyoxyethylene Ester Formulations

Adjuvants suitable for use in the invention include polyoxyethylene ethers and polyoxyethylene esters [78]. Such formulations further include polyoxyethylene sorbitan ester surfactants in combination with an octoxynol [79] as well as polyoxyethylene alkyl ethers or ester surfactants in combination with at least one additional non-ionic surfactant such as an octoxynol [80]. Preferred polyoxyethylene ethers are selected from the following group: polyoxyethylene-9-lauryl ether (laureth 9), polyoxyethylene-9-steoryl ether, polyoxytheylene-8-steoryl ether, polyoxyethylene-4-lauryl ether, polyoxyethylene-35-lauryl ether, and polyoxyethylene-23-lauryl ether.

K. Polyphosphazene (PCPP)

PCPP formulations are described, for example, in refs. 81 and 82.

L. Muramyl Peptides

Examples of muramyl peptides suitable for use as adjuvants in the invention include N-acetyl-muramyl-L-threonyl-D-isoglutamine (thr-MDP), N-acetyl-normuramyl-L-alanyl-D-isoglutamine (nor-MDP), and N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-alanine-2-(1′-2′-dipalmitoyl-sn-glycero-3-hydroxyphosphoryloxy)-ethylamine MTP-PE).

M. Imidazoquinoline Compounds.

Examples of imidazoquinoline compounds suitable for use adjuvants in the invention include Imiquamod and its homologues (e,g. “Resiquimod 3M”), described further in refs. 83 and 84.

The invention may also comprise combinations of aspects of one or more of the adjuvants identified above. For example, the following adjuvant compositions may be used in the invention: (1) a saponin and an oil-in-water emulsion [85]; (2) a saponin (e.g. QS21)+a non-toxic LPS derivative (e.g. 3dMPL) [86]; (3) a saponin (e.g. QS21)+a non-toxic LPS derivative (e.g. 3dMPL)+a cholesterol; (4) a saponin (e.g. QS21)+3dMPL+IL-12 (optionally+a sterol) [87]; (5) combinations of 3dMPL with, for example, QS21 and/or oil-in-water emulsions [88]; (6) SAF, containing 10% squalane, 0.4% Tween 80™, 5% pluronic-block polymer L121, and thr-MDP, either microfluidized into a submicron emulsion or vortexed to generate a larger particle size emulsion. (7) Ribi™ adjuvant system (RAS), (Ribi Immunochem) containing 2% squalene, 0.2% Tween 80, and one or more bacterial cell wall components from the group consisting of monophosphorylipid A (MPL), trehalose dimycolate (TDM), and cell wall skeleton (CWS), preferably MPL+CWS (Detox™); and (8) one or more mineral salts (such as an aluminum salt)+a non-toxic derivative of LPS (such as 3dMPL).

Other substances that act as immunostimulating agents are disclosed in chapter 7 of ref. 22.

Aluminium salts (aluminium phosphates and particularly hydroxyphosphates, and/or hydroxides and particularly oxyhydroxide) and MF59 are preferred adjuvants for parenteral immunisation. Toxin mutants are preferred mucosal adjuvants. QS21 is another useful adjuvant for NMB1870, which may be used alone or in combination with one or more other adjuvants e.g. with an aluminium salt.

Muramyl peptides include N-acetyl-muramyl-L-threonyl-D-isoglutamine (thr-MDP), N-acetyl-normuramyl-L-alanyl-D-isoglutamine (nor-MDP), N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-alanine-2-(1′-2′-dipalmitoyl-sn-glycero-3-hydroxyphosphoryloxy)-ethylamine MTP-PE), etc.

Further Antigenic Components

Compositions of the invention include NMB1870 sequences. It is particularly preferred that the composition should not include complex or undefined mixtures of antigens e.g. it is preferred not to include outer membrane vesicles in the composition. Polypeptides of the invention are preferably expressed recombinantly in a heterologous host and then purified.

As well as including a NMB1870 sequence, a composition of the invention may also include one or more further neisserial antigen(s), as a vaccine which targets more than one antigen per bacterium decreases the possibility of selecting escape mutants. Neisserial antigens for inclusion in the compositions include polypeptides comprising one or more of:

-   -   (a) the 446 even SEQ IDs (i.e. 2, 4, 6, . . . , 890, 892)         disclosed in reference 89.     -   (b) the 45 even SEQ IDs (i.e. 2, 4, 6, . . . , 88, 90) disclosed         in reference 90;     -   (c) the 1674 even SEQ IDs 2-3020, even SEQ IDs 3040-3114, and         all SEQ IDs 3115-3241, disclosed in reference 3;     -   (d) the 2160 amino acid sequences NMB0001 to NMB2160 from         reference 2;     -   (e) a meningococcal PorA protein, of any subtype, preferably         recombinantly expressed;     -   (f) a variant, homolog, ortholog, paralog, mutant etc. of (a) to         (e); or     -   (g) an outer membrane vesicle preparation from N. meningitidis         [e.g. see ref. 182].

In addition to Neisserial polypeptide antigens, the composition may include antigens for immunising against other diseases or infections. For example, the composition may include one or more of the following further antigens:

-   -   a saccharide antigen from N. meningitidis serogroup A, C, W135         and/or Y, such as the oligosaccharide disclosed in ref. 91 from         serogroup C [see also ref. 92] or the oligosaccharides of ref.         93.     -   a saccharide antigen from Streptococcus pneumoniae [e.g. 94, 95,         96].     -   an antigen from hepatitis A virus, such as inactivated virus         [e.g. 97, 98].     -   an antigen from hepatitis B virus, such as the surface and/or         core antigens [e.g. 98, 99].     -   a diphtheria antigen, such as a diphtheria toxoid [e.g. chapter         3 of ref. 100] e.g. the CRM₁₉₇ mutant [e.g. 101].     -   a tetanus antigen, such as a tetanus toxoid [e.g. chapter 4 of         ref. 100].     -   an antigen from Bordetella pertussis, such as pertussis         holotoxin (PT) and filamentous haemagglutinin (FHA) from B.         pertussis, optionally also in combination with pertactin and/or         agglutinogens 2 and 3 [e.g. refs. 102 & 103].     -   a saccharide antigen from Haemophilus influenzae B [e.g. 92].     -   polio antigen(s) [e.g. 104, 105] such as IPV.     -   measles, mumps and/or rubella antigens [e.g. chapters 9, 10 & 11         of ref. 100].     -   influenza antigen(s) [e.g. chapter 19 of ref 100], such as the         haemagglutinin and/or neuraminidase surface proteins.     -   an antigen from Moraxella catarrhalis [e.g. 106].     -   an protein antigen from Streptococcus agalactiae (group B         streptococcus) [e.g. 107, 108].     -   a saccharide antigen from Streptococcus agalactiae (group B         streptococcus).     -   an antigen from Streptococcus pyogenes (group A         streptococcus)[e.g. 108, 109, 110].     -   an antigen from Staphylococcus aureus [e.g. 111].

The composition may comprise one or more of these further antigens.

Toxic protein antigens may be detoxified where necessary (e.g. detoxification of pertussis toxin by chemical and/or genetic means [103]).

Where a diphtheria antigen is included in the composition it is preferred also to include tetanus antigen and pertussis antigens. Similarly, where a tetanus antigen is included it is preferred also to include diphtheria and pertussis antigens. Similarly, where a pertussis antigen is included it is preferred also to include diphtheria and tetanus antigens. DTP combinations are thus preferred.

Saccharide antigens are preferably in the form of conjugates. Carrier proteins for the conjugates are discussed in more detail below.

Antigens in the composition will typically be present at a concentration of at least 1 g/ml each. In general, the concentration of any given antigen will be sufficient to elicit an immune response against that antigen.

Immunogenic compositions of the invention may be used therapeutically (i.e. to treat an existing infection) or prophylactically (i.e. to prevent future infection).

As an alternative to using proteins antigens in the immunogenic compositions of the invention, nucleic acid (preferably DNA e.g. in the form of a plasmid) encoding the antigen may be used.

Particularly preferred compositions of the invention include one, two or three of: (a) saccharide antigens from meningococcus serogroups Y, W135, C and (optionally) A; (b) a saccharide antigen from Haemophilus influenzae type B; and/or (c) an antigen from Streptococcus pneumoniae.

Meningococcus Serogroups Y, W135, C and (Optionally) A

Polysaccharide vaccines against serogroups A, C, W135 & Y have been known for many years. These vaccines (MENCEVAX ACWY™ and MENOMUNE™) are based on the organisms' capsular polysaccharides and, although they are effective in adolescents and adults, they give a poor immune response and short duration of protection, and they cannot be used in infants.

In contrast to the unconjugated polysaccharide antigens in these vaccines, the recently-approved serogroup C vaccines (Menjugate™ [112,91], Meningitec™ and NeisVac-C™) include conjugated saccharides. Menjugate™ and Meningitec™ have oligosaccharide antigens conjugated to a CRM₁₉₇ carrier, whereas NeisVac-C™ uses the complete polysaccharide (de-O-acetylated) conjugated to a tetanus toxoid carrier. The Menactra™ vaccine contains conjugated capsular saccharide antigens from each of serogroups Y, W135, C and A.

Compositions of the present invention preferably include capsular saccharide antigens from one or more of meningococcus serogroups Y, W135, C and (optionally) A, wherein the antigens are conjugated to carrier protein(s) and/or are oligosaccharides. For example, the composition may include a capsular saccharide antigen from: serogroup C; serogroups A and C; serogroups A, C and W135; serogroups A, C and Y; serogroups C, W135 and Y; or from all four of serogroups A, C, W135 and Y.

A typical quantity of each meningococcal saccharide antigen per dose is between 1 μg and 20 μg e.g. about 1 μg, about 2.5 μg, about 4 μg, about 5 μg, or about 10 μg (expressed as saccharide).

Where a mixture comprises capsular saccharides from both serogroups A and C, the ratio (w/w) of MenA saccharide:MenC saccharide may be greater than 1 (e.g. 2:1, 3:1, 4:1, 5:1, 10:1 or higher).

Where a mixture comprises capsular saccharides from serogroup Y and one or both of serogroups C and W135, the ratio (w/w) of MenY saccharide:MenW135 saccharide may be greater than 1 (e.g. 2:1, 3:1, 4:1, 5:1, 10:1 or higher) and/or that the ratio (w/w) of MenY saccharide:MenC saccharide may be less than 1 (e.g. 1:2, 1:3, 1:4, 1:5, or lower). Preferred ratios (w/w) for saccharides from serogroups A:C:W135:Y are: 1:1:1:1; 1:1:1:2; 2:1:1:1; 4:2:1:1; 8:4:2:1; 4:2:1:2; 8:4:1:2; 4:2:2:1; 2:2:1:1; 4:4:2:1; 2:2:1:2; 4:4:1:2; and 2:2:2:1. Preferred ratios (w/w) for saccharides from serogroups C:W135:Y are: 1:1:1; 1:1:2; 1:1:1; 2:1:1; 4:2:1; 2:1:2; 4:1:2; 2:2:1; and 2:1:1. Using a substantially equal mass of each saccharide is preferred.

Capsular saccharides will generally be used in the form of oligosaccharides. These are conveniently formed by fragmentation of purified capsular polysaccharide (e.g. by hydrolysis), which will usually be followed by purification of the fragments of the desired size.

Fragmentation of polysaccharides is preferably performed to give a final average degree of polymerisation (DP) in the oligosaccharide of less than 30 (e.g. between 10 and 20, preferably around 10 for serogroup A; between 15 and 25 for serogroups W135 and Y, preferably around 15-20; between 12 and 22 for serogroup C; etc.). DP can conveniently be measured by ion exchange chromatography or by colorimetric assays [113].

If hydrolysis is performed, the hydrolysate will generally be sized in order to remove short-length oligosaccharides [92]. This can be achieved in various ways, such as ultrafiltration followed by ion-exchange chromatography. Oligosaccharides with a degree of polymerisation of less than or equal to about 6 are preferably removed for serogroup A, and those less than around 4 are preferably removed for serogroups W135 and Y.

Preferred MenC saccharide antigens are disclosed in reference 112, as used in Menjugate™.

The saccharide antigen may be chemically modified. This is particularly useful for reducing hydrolysis for serogroup A [114; see below]. De-O-acetylation of meningococcal saccharides can be performed. For oligosaccharides, modification may take place before or after depolymerisation.

Where a composition of the invention includes a MenA saccharide antigen, the antigen is preferably a modified saccharide in which one or more of the hydroxyl groups on the native saccharide has/have been replaced by a blocking group [114]. This modification improves resistance to hydrolysis.

Meningococcal capsular polysaccharides are typically prepared by a process comprising the steps of polysaccharide precipitation (e.g. using a cationic detergent), ethanol fractionation, cold phenol extraction (to remove protein) and ultracentrifugation (to remove LPS) [e.g. ref. 115]. A more preferred process [93], however, involves polysaccharide precipitation followed by solubilisation of the precipitated polysaccharide using a lower alcohol. Precipitation can be achieved using a cationic detergent such as tetrabutylammonium and cetyltrimethylammonium salts (e.g. the bromide salts), or hexadimethrine bromide and myristyltrimethylammonium salts. Cetyltrimethylammonium bromide (‘CTAB’) is particularly preferred [116]. Solubilisation of the precipitated material can be achieved using a lower alcohol such as methanol, propan-1-ol, propan-2-ol, butan-1-ol, butan-2-ol, 2-methyl-propan-1-ol, 2-methyl-propan-2-ol, diols, etc., but ethanol is particularly suitable for solubilising CTAB-polysaccharide complexes. Ethanol is preferably added to the precipitated polysaccharide to give a final concentration (based on total content of ethanol and water) of between 50% and 95%.

After re-solubilisation, the polysaccharide may be further treated to remove contaminants. This is particularly important in situations where even minor contamination is not acceptable (e.g. for human vaccine production). This will typically involve one or more steps of filtration e.g. depth filtration, filtration through activated carbon may be used, size filtration and/or ultrafiltration. Once filtered to remove contaminants, the polysaccharide may be precipitated for further treatment and/or processing. This can be conveniently achieved by exchanging cations (e.g. by the addition of calcium or sodium salts).

As an alternative to purification, capsular saccharides may be obtained by total or partial synthesis e.g. Hib synthesis is disclosed in ref. 117, and MenA synthesis in ref. 118.

Compositions of the invention comprise capsular saccharides from at least two serogroups of N. meningitidis. The saccharides are preferably prepared separately (including any fragmentation, conjugation, modification, etc.) and then admixed to give a composition of the invention.

Where the composition comprises capsular saccharide from serogroup A, however, it is preferred that the serogroup A saccharide is not combined with the other saccharide(s) until shortly before use, in order to minimise the potential for hydrolysis. This can conveniently be achieved by having the serogroup A component (typically together with appropriate excipients) in lyophilised form and the other serogroup component(s) in liquid form (also with appropriate excipients), with the liquid components being used to reconstitute the lyophilised MenA component when ready for use. Where an aluminium salt adjuvant is used, it is preferred to include the adjuvant in the vial containing the with the liquid vaccine, and to lyophilise the MenA component without adjuvant.

A composition of the invention may thus be prepared from a kit comprising: (a) capsular saccharide from N. meningitidis serogroup A, in lyophilised form; and (b) the further antigens from the composition, in liquid form. The invention also provides a method for preparing a composition of the invention, comprising mixing a lyophilised capsular saccharide from N. meningitidis serogroup A with the further antigens, wherein said further antigens are in liquid form.

The invention also provides a kit comprising: (a) a first container containing capsular saccharides from two or more of N. meningitidis serogroups C, W135 and Y, all in lyophilised form; and (b) a second container containing in liquid form (i) a composition which, after administration to a subject, is able to induce an antibody response in that subject, wherein the antibody response is bactericidal against two or more (e.g. 2 or 3) of hypervirulent lineages A4, ET-5 and lineage 3 of N. meningitidis serogroup B, (ii) capsular saccharides from none or one of N. meningitidis serogroups C, W135 and Y, and optionally (iii) further antigens (see below) that do not include meningococcal capsular saccharides, wherein, reconstitution of the contents of container (a) by the contents of container (b) provides a composition of the invention.

Within each dose, the amount of an individual saccharide antigen will generally be between 1-50 μg (measured as mass of saccharide), with about 2.5 μg, 5 μg or 10 μg of each being preferred. With A:C:W135:Y weight ratios of 1:1:1:1; 1:1:1:2; 2:1:1:1; 4:2:1:1; 8:4:2:1; 4:2:1:2; 8:4:1:2; 4:2:2:1; 2:2:1:1; 4:4:2:1; 2:2:1:2; 4:4:1:2; and 2:2:2:1, therefore, the amount represented by the number 1 is preferably about 2.5 μg, 5 μg or 10 μg. For a 1:1:1:1 ratio A:C:W:Y composition and a 10 μg per saccharide, therefore, 40 μg saccharide is administered per dose. Preferred compositions have about the following μg saccharide per dose:

A 10 0 0 0 10 5 2.5 C 10 10 5 2.5 5 5 2.5 W135 10 10 5 2.5 5 5 2.5 Y 10 10 5 2.5 5 5 2.5

Preferred compositions of the invention comprise less than 50 μg meningococcal saccharide per dose. Other preferred compositions comprise ≦40 μg meningococcal saccharide per dose. Other preferred compositions comprise ≦30 μg meningococcal saccharide per dose. Other preferred compositions comprise ≦25 μg meningococcal saccharide per dose. Other preferred compositions comprise ≦20 μg meningococcal saccharide per dose. Other preferred compositions comprise ≦10 μg meningococcal saccharide per dose but, ideally, compositions of the invention comprise at least 10 μg meningococcal saccharide per dose.

The Menjugate™ and NeisVac™ MenC conjugates use a hydroxide adjuvant, whereas Meningitec™ uses a phosphate. It is possible in compositions of the invention to adsorb some antigens to an aluminium hydroxide but to have other antigens in association with an aluminium phosphate. For tetravalent serogroup combinations, for example, the following permutations are available:

Serogroup Aluminium salt (H = a hydroxide; P = a phosphate) A P H P H H H P P P H H H P P P H C P H H P H H P H H P P H P H P P W135 P H H H P H H P H H P P P P H P Y P H H H H P H H P P H P H P P P

For trivalent N. meningitidis serogroup combinations, the following permutations are available:

Serogroup Aluminium salt (H = a hydroxide; P = a phosphate) C P H H H P P P H W135 P H H P H P H P Y P H P H H H P P

Haemophilus influenzae Type B

Where the composition includes a H. influenzae type b antigen, it will typically be a Hib capsular saccharide antigen. Saccharide antigens from H. influenzae b are well known.

Advantageously, the Hib saccharide is covalently conjugated to a carrier protein, in order to enhance its immunogenicity, especially in children. The preparation of polysaccharide conjugates in general, and of the Hib capsular polysaccharide in particular, is well documented [e.g. references 119 to 127 etc.]. The invention may use any suitable Hib conjugate. Suitable carrier proteins are described below, and preferred carriers for Hib saccharides are CRM₁₉₇ (‘HbOC’), tetanus toxoid (‘PRP-T’) and the outer membrane complex of N. meningitidis (‘PRP-OMP’).

The saccharide moiety of the conjugate may be a polysaccharide (e.g. full-length polyribosylribitol phosphate (PRP)), but it is preferred to hydrolyse polysaccharides to form oligosaccharides (e.g. MW from ˜1 to 5 kDa).

A preferred conjugate comprises a Hib oligosaccharide covalently linked to CRM₁₉₇ via an adipic acid linker [128, 129]. Tetanus toxoid is also a preferred carrier.

Compositions of the invention may comprise more than one Hib antigen.

Where a composition includes a Hib saccharide antigen, it is preferred that it does not also include an aluminium hydroxide adjuvant. If the composition includes an aluminium phosphate adjuvant then the Hib antigen may be adsorbed to the adjuvant [130] or it may be non-adsorbed [131].

Hib antigens may be lyophilised e.g. together with meningococcal antigens.

Streptococcus pneumoniae

Where the composition includes a S. pneumoniae antigen, it will typically be a capsular saccharide antigen which is preferably conjugated to a carrier protein [e.g. refs. 94-96]. It is preferred to include saccharides from more than one serotype of S. pneumoniae. For example, mixtures of polysaccharides from 23 different serotype are widely used, as are conjugate vaccines with polysaccharides from between 5 and 11 different serotypes [132]. For example, PrevNar™ [133] contains antigens from seven serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) with each saccharide individually conjugated to CRM₁₉₇ by reductive amination, with 2 μg of each saccharide per 0.5 ml dose (4 μg of serotype 6B), and with conjugates adsorbed on an aluminium phosphate adjuvant. Compositions of the invention preferably include at least serotypes 6B, 14, 19F and 23F. Conjugates may be adsorbed onto an aluminium phosphate.

As an alternative to using saccharide antigens from pneumococcus, the composition may include one or more polypeptide antigens. Genome sequences for several strains of pneumococcus are available [134,135] and can be subjected to reverse vaccinology [136-139] to identify suitable polypeptide antigens [140,141]. For example, the composition may include one or more of the following antigens: PhtA, PhtD, PhtB, PhtE, SpsA, LytB, LytC, LytA, Sp125, Sp101, Sp128 and Sp130, as defined in reference 142.

In some embodiments, the composition may include both saccharide and polypeptide antigens from pneumococcus. These may be used in simple admixture, or the pneumococcal saccharide antigen may be conjugated to a pneumococcal protein. Suitable carrier proteins for such embodiments include the antigens listed in the previous paragraph [142].

Pneumococcal antigens may be lyophilised e.g. together with meningococcal and/or Hib antigens.

Covalent Conjugation

Capsular saccharides in compositions of the invention will usually be conjugated to carrier protein(s). In general, conjugation enhances the immunogenicity of saccharides as it converts them from T-independent antigens to T-dependent antigens, thus allowing priming for immunological memory. Conjugation is particularly useful for paediatric vaccines and is a well known technique [e.g. reviewed in refs. 143 and 119-127].

Preferred carrier proteins are bacterial toxins or toxoids, such as diphtheria toxoid or tetanus toxoid. The CRM₁₉₇ mutant diphtheria toxin [144,145,146] is particularly preferred. Other suitable carrier proteins include the N. meningitidis outer membrane protein [147], synthetic peptides [148,149], heat shock proteins [150,151], pertussis proteins [152,153], protein D from H. influenzae [154,155], cytokines [156], lymphokines [156], artificial proteins comprising multiple human CD4+ T cell epitopes from various pathogen-derived antigens [157], streptococcal proteins, hormones [156], growth factors [156], pneumococcal surface protein PspA [158], toxin A or B from C. difficile [159], iron-uptake proteins [160], etc. A preferred carrier protein is CRM 197.

Within a composition of the invention, it is possible to use more than one carrier protein e.g. to reduce the risk of carrier suppression. Thus different carrier proteins can be used for different serogroups e.g. serogroup A saccharides might be conjugated to CRM₁₉₇ while serogroup C saccharides might be conjugated to tetanus toxoid. It is also possible to use more than one carrier protein for a particular saccharide antigen e.g. serogroup A saccharides might be in two groups, with some conjugated to CRM₁₉₇ and others conjugated to tetanus toxoid. In general, however, it is preferred to use the same carrier protein for all saccharides.

A single carrier protein might carry more than one saccharide antigen [161]. For example, a single carrier protein might have conjugated to it saccharides from serogroups A and C. To achieve this goal, saccharides can be mixed prior to the conjugation reaction. In general, however, it is preferred to have separate conjugates for each serogroup.

Conjugates with a saccharide:protein ratio (w/w) of between 1:5 (i.e. excess protein) and 5:1 (i.e. excess saccharide) are preferred. Ratios between 1:2 and 5:1 are preferred, as are ratios between 1:1.25 and 1:2.5 are more preferred. Excess carrier protein is preferred for MenA and MenC.

Conjugates may be used in conjunction with free carrier protein [162]. When a given carrier protein is present in both free and conjugated form in a composition of the invention, the unconjugated form is preferably no more than 5% of the total amount of the carrier protein in the composition as a whole, and more preferably present at less than 2% by weight.

Any suitable conjugation reaction can be used, with any suitable linker where necessary.

The saccharide will typically be activated or functionalised prior to conjugation. Activation may involve, for example, cyanylating reagents such as CDAP (e.g. 1-cyano-4-dimethylamino pyridinium tetrafluoroborate [163,164,etc.]). Other suitable techniques use carbodiimides, hydrazides, active esters, norborane, p-nitrobenzoic acid, N-hydroxysuccinimide, S-NHS, EDC, TSTU; see also the introduction to reference 125).

Linkages via a linker group may be made using any known procedure, for example, the procedures described in references 165 and 166. One type of linkage involves reductive amination of the polysaccharide, coupling the resulting amino group with one end of an adipic acid linker group, and then coupling a protein to the other end of the adipic acid linker group [123,167,168]. Other linkers include B-propionamido [169], nitrophenyl-ethylamine [170], haloacyl halides [171], glycosidic linkages [172], 6-aminocaproic acid [173], ADH [174], C₄ to C₁₂ moieties [175] etc. As an oxidation of the polysaccharide followed by reductive amination with the protein, as described in, for example, references 176 and 177.

A process involving the introduction of amino groups into the saccharide (e.g. by replacing terminal ═O groups with —NH₂) followed by derivatisation with an adipic diester (e.g. adipic acid N-hydroxysuccinimido diester) and reaction with carrier protein is preferred. Another preferred reaction uses CDAP activation with a protein D carrier e.g. for MenA or MenC.

After conjugation, free and conjugated saccharides can be separated. There are many suitable methods, including hydrophobic chromatography, tangential ultrafiltration, diafiltration etc. [see also refs. 178 & 179, etc.].

Where the composition of the invention includes a conjugated oligosaccharide, it is preferred that oligosaccharide preparation precedes conjugation.

Outer Membrane Vesicles It is preferred that compositions of the invention should not include complex or undefined mixtures of antigens, which are typical characteristics of OMVs. However, the invention can be used in conjunction with OMVs, as NMB1870 has been found to enhance their efficacy [6], in particular by over-expressing the polypeptides of the invention in the strains used for OMV preparation.

This approach may be used in general to improve preparations of N. meningitidis serogroup B microvesicles [180], ‘native OMVs’ [181], blebs or outer membrane vesicles [e.g. refs. 182 to 187, etc.]. These may be prepared from bacteria which have been genetically manipulated [188-191] e.g. to increase immunogenicity (e.g. hyper-express immunogens), to reduce toxicity, to inhibit capsular polysaccharide synthesis, to down-regulate PorA expression, etc. They may be prepared from hyperblebbing strains [192-195]. Vesicles from a non-pathogenic Neisseria may be included [196]. OMVs may be prepared without the use of detergents [197,198]. They may express non-Neisserial proteins on their surface [199]. They may be LPS-depleted. They may be mixed with recombinant antigens [182,200]. Vesicles from bacteria with different class I outer membrane protein subtype may be used e.g. six different subtypes [201,202] using two different genetically-engineered vesicle populations each displaying three subtypes, or nine different subtypes using three different genetically-engineered vesicle populations each displaying three subtypes, etc. Useful subtypes include: P1.7,16; P1.5-1,2-2; P1.19,15-1; P1.5-2,10; P1.12-1,13; P1.7-2,4; P1.22,14; P1.7-1,1; P1.18-1,3,6.

Protein Expression

Bacterial expression techniques are known in the art. A bacterial promoter is any DNA sequence capable of binding bacterial RNA polymerase and initiating the downstream (3′) transcription of a coding sequence (e.g. structural gene) into mRNA. A promoter will have a transcription initiation region which is usually placed proximal to the 5′ end of the coding sequence. This transcription initiation region usually includes an RNA polymerase binding site and a transcription initiation site. A bacterial promoter may also have a second domain called an operator, that may overlap an adjacent RNA polymerase binding site at which RNA synthesis begins. The operator permits negative regulated (inducible) transcription, as a gene repressor protein may bind the operator and thereby inhibit transcription of a specific gene. Constitutive expression may occur in the absence of negative regulatory elements, such as the operator. In addition, positive regulation may be achieved by a gene activator protein binding sequence, which, if present is usually proximal (5′) to the RNA polymerase binding sequence. An example of a gene activator protein is the catabolite activator protein (CAP), which helps initiate transcription of the lac operon in Escherichia coli (E. coli) [Raibaud et al. (1984) Annu. Rev. Genet 18:173]. Regulated expression may therefore be either positive or negative, thereby either enhancing or reducing transcription.

Sequences encoding metabolic pathway enzymes provide particularly useful promoter sequences.

Examples include promoter sequences derived from sugar metabolizing enzymes, such as galactose, lactose (lac) [Chang et al. (1977) Nature 198:1056], and maltose. Additional examples include promoter sequences derived from biosynthetic enzymes such as tryptophan (trp) [Goeddel et al. (1980) Nuc. Acids Res. 8:4057; Yelverton et al. (1981) Nucl. Acids Res. 9:731; U.S. Pat. No. 4,738,921; EP-A-0036776 and EP-A-0121775]. The β-lactamase (blα) promoter system [Weissmann (1981) “The cloning of interferon and other mistakes.” In Interferon 3 (ed. I. Gresser)], bacteriophage lambda PL [Shimatake et al. (1981) Nature 292:128] and T5 [U.S. Pat. No., 4,689,406] promoter systems also provide useful promoter sequences. Another promoter of interest is an inducible arabinose promoter (pBAD).

In addition, synthetic promoters which do not occur in nature also function as bacterial promoters.

For example, transcription activation sequences of one bacterial or bacteriophage promoter may be joined with the operon sequences of another bacterial or bacteriophage promoter, creating a synthetic hybrid promoter [U.S. Pat. No. 4,551,433]. For example, the tac promoter is a hybrid trp-lac promoter comprised of both trp promoter and lac operon sequences that is regulated by the lac repressor [Amann et al. (1983) Gene 25:167; de Boer et al. (1983) Proc. Natl. Acad. Sci. 80:21]. Furthermore, a bacterial promoter can include naturally occurring promoters of non-bacterial origin that have the ability to bind bacterial RNA polymerase and initiate transcription. A naturally occurring promoter of non-bacterial origin can also be coupled with a compatible RNA polymerase to produce high levels of expression of some genes in prokaryotes. The bacteriophage T7 RNA polymerase/promoter system is an example of a coupled promoter system [Studier et al. (1986) J. Mol. Biol. 189:113; Tabor et al. (1985) Proc Natl. Acad. Sci. 82:1074]. In addition, a hybrid promoter can also be comprised of a bacteriophage promoter and an E. coli operator region (EPO-A-0 267 851).

In addition to a functioning promoter sequence, an efficient ribosome binding site is also useful for the expression of foreign genes in prokaryotes. In E. coli, the ribosome binding site is called the Shine-Dalgarno (SD) sequence and includes an initiation codon (ATG) and a sequence 3-9 nucleotides in length located 3-11 nucleotides upstream of the initiation codon. The SD sequence is thought to promote binding of mRNA to the ribosome by the pairing of bases between the SD sequence and the 3′ and of E. coli 16S rRNA [Steitz et al. (1979) “Genetic signals and nucleotide sequences in messenger RNA.” In Biological Regulation and Development: Gene Expression (ed. R. F. Goldberger)]. To express eukaryotic genes and prokaryotic genes with weak ribosome-binding site [Sambrook et al. (1989) “Expression of cloned genes in Escherichia coli.” In Molecular Cloning: A Laboratory Manual].

A promoter sequence may be directly linked with the DNA molecule, in which case the first amino acid at the N-terminus will always be a methionine, which is encoded by the ATG start codon. If desired, methionine at the N-terminus may be cleaved from the protein by in vitro incubation with cyanogen bromide or by either in vivo on in vitro incubation with a bacterial methionine N-terminal peptidase (EP-A-0219237).

Usually, transcription termination sequences recognized by bacteria are regulatory regions located 3′ to the translation stop codon, and thus together with the promoter flank the coding sequence. These sequences direct the transcription of an mRNA which can be translated into the polypeptide encoded by the DNA. Transcription termination sequences frequently include DNA sequences of about 50 nucleotides capable of forming stem loop structures that aid in terminating transcription. Examples include transcription termination sequences derived from genes with strong promoters, such as the trp gene in E. coli as well as other biosynthetic genes.

Usually, the above described components, comprising a promoter, signal sequence (if desired), coding sequence of interest, and transcription termination sequence, are put together into expression constructs. Expression constructs are often maintained in a replicon, such as an extrachromosomal element (e.g. plasmids) capable of stable maintenance in a host, such as bacteria. The replicon will have a replication system, thus allowing it to be maintained in a prokaryotic host either for expression or for cloning and amplification. In addition, a replicon may be either a high or low copy number plasmid. A high copy number plasmid will generally have a copy number ranging from about 5 to about 200, and usually about 10 to about 150. A host containing a high copy number plasmid will preferably contain at least about 10, and more preferably at least about 20 plasmids. Either a high or low copy number vector may be selected, depending upon the effect of the vector and the foreign protein on the host.

Alternatively, the expression constructs can be integrated into the bacterial genome with an integrating vector. Integrating vectors usually contain at least one sequence homologous to the bacterial chromosome that allows the vector to integrate. Integrations appear to result from recombinations between homologous DNA in the vector and the bacterial chromosome. For example, integrating vectors constructed with DNA from various Bacillus strains integrate into the Bacillus chromosome (EP-A-0127328). Integrating vectors may also be comprised of bacteriophage or transposon sequences.

Usually, extrachromosomal and integrating expression constructs may contain selectable markers to allow for the selection of bacterial strains that have been transformed. Selectable markers can be expressed in the bacterial host and may include genes which render bacteria resistant to drugs such as ampicillin, chloramphenicol, erythromycin, kanamycin (neomycin), and tetracycline [Davies et al. (1978) Annu. Rev. Microbiol. 32:469]. Selectable markers may also include biosynthetic genes, such as those in the histidine, tryptophan, and leucine biosynthetic pathways.

Alternatively, some of the above described components can be put together in transformation vectors. Transformation vectors are usually comprised of a selectable market that is either maintained in a replicon or developed into an integrating vector, as described above.

Expression and transformation vectors, either extra-chromosomal replicons or integrating vectors, have been developed for transformation into many bacteria. For example, expression vectors have been developed for, inter alia, the following bacteria: Bacillus subtilis [Palva et al. (1982) Proc. Natl. Acad. Sci. USA 79:5582; EP-A-0 036 259 and EP-A-0 063 953; WO 84/04541], Escherichia coli [Shimatake et al. (1981) Nature 292:128; Amann et al. (1985) Gene 40:183; Studier et al. (1986) J. Mol. Biol. 189:113; EP-A-0 036 776,EP-A-0 136 829 and EP-A-0 136 907], Streptococcus cremoris [Powell et al. (1988) Appl. Environ. Microbiol. 54:655]; Streptococcus lividans [Powell et al. (1988) Appl. Environ. Microbiol. 54:655], Streptomyces lividans [U.S. Pat. No, 4,745,056].

Methods of introducing exogenous DNA into bacterial hosts are well-known in the art, and usually include either the transformation of bacteria treated with CaCl₂ or other agents, such as divalent cations and DMSO. DNA can also be introduced into bacterial cells by electroporation. Transformation procedures usually vary with the bacterial species to be transformed. See e.g. [Masson et al. (1989) FEMS Microbiol. Lett. 60:273; Palva et al. (1982) Proc. Natl. Acad Sci. USA 79:5582; EP-A-0 036 259 and EP-A-0 063 953; WO 84/04541, Bacillus], [Miller et al. (1988) Proc. Natl. Acad. Sci. 85:856; Wang et al. (1990) J. Bacteriol. 172:949, Campylobacter], [Cohen et al. (1973) Proc. Natl. Acad Sci. 69:2110; Dower et al. (1988) Nucleic Acids Res. 16:6127; Kushner (1978) “An improved method for transformation of Escherichia coli with ColE1-derived plasmids. In Genetic Engineering: Proceedings of the International Symposium on Genetic Engineering (eds. H. W. Boyer and S. Nicosia); Mandel et al. (1970) J. Mol. Biol. 53:159; Taketo (1988) Biochim. Biophys. Acta 949:318; Escherichia], [Chassy et al. (1987) FEMS Microbiol. Lett. 44:173 Lactobacillus]; [Fiedler et al. (1988) Anal. Biochem 170:38, Pseudomonas]; [Augustin et al. (1990) FEMS Microbiol. Lett. 66:203, Staphylococcus], [Barany et al. (1980) J. Bacteriol. 144:698; Harlander (1987) “Transformation of Streptococcus lactis by electroporation, in: Streptococcal Genetics (ed. J. Ferretti and R. Curtiss III); Perry et al. (1981) Infect. Immun. 32:1295; Powell et al. (1988) Appl. Environ. Microbiol. 54:655; Somkuti et al. (1987) Proc. 4th Evr. Cong. Biotechnology 1:412, Streptococcus].

General

The term “comprising” encompasses “including” as well as “consisting” e.g. a composition “comprising” X may consist exclusively of X or may include something additional e.g. X+Y.

The term “about” in relation to a numerical value x means, for example, x±10%.

The word “substantially” does not exclude “completely” e.g. a composition which is “substantially free” from Y may be completely free from Y. Where necessary, the word “substantially” may be omitted from the definition of the invention.

“Sequence identity” is preferably determined by the Smith-Waterman homology search algorithm as implemented in the MPSRCH program (Oxford Molecular), using an affine gap search with parameters gap open penalty=12 and gap extension penalty=1.

After serogroup, meningococcal classification includes serotype, serosubtype and then immunotype, and the standard nomenclature lists serogroup, serotype, serosubtype, and immunotype, each separated by a colon e.g. B:4:P1.15:L3,7,9. Within serogroup B, some lineages cause disease often (hyperinvasive), some lineages cause more severe forms of disease than others (hypervirulent), and others rarely cause disease at all. Seven hypervirulent lineages are recognised, namely subgroups I, III and IV-1, ET-5 complex, ET-37 complex, A4 cluster and lineage 3. These have been defined by multilocus enzyme electrophoresis (MLEE), but multilocus sequence typing (MLST) has also been used to classify meningococci [ref. 18]. The four main hypervirulent clusters are ST32, ST44, ST8 and ST11 complexes.

In general, the invention does not encompass the various NMB1870 sequences specifically disclosed in references 4, 5, 7, 8, 9, 10, 11, 12, 13 and 203, although these NMB1870 sequences may be used according to the invention e.g. for the construction of chimeric sequences, etc.

MODES FOR CARRYING OUT THE INVENTION

Substitutions

SEQ ID NO: 59 is disclosed in reference 13 as a chimera of NMB1870 from families I, II & III. This polypeptide is derived by substitutions in seven regions of SEQ ID NO:1, identified below:

{SEQ ID NO: 1) MNRTAFCCLSLTTALILTACSSGGGGVAADIGAGLADALTAPLDHKDKG LQSLTLDQSVRKNEKLKLAAQGAEKTYGNGDSLNTGKLKNDKVSRFDFI RQIEVDGQLITLESGEFQVYKQSHSALTAFQTEQIQDSEHSGKMVAKRQ FRIGDIAGEHTSFDKLPEGGRATYRGTAFGSDDAGGKLTYTIDFAAKQG NGKIEHLKSPELNVDLAAADIKPDGKRHAVISGSVLYNQAEKGSYSLGI FGGKAQEVAGSAEVKTVNGIRHIGLAAKQ 

Although this chimera elicited antibodies that were bactericidal against meningococci from each NMB1870 family, responses against family H and family III strains were not consistently high.

By combining various approaches, including a NMR-derived 3D structure of the BC domain of a family I polypeptide, the inventors found that residues 162-168 (second underlined region) are surrounded by a patch of amino acids which are conserved between meningococcal MC58 (family I) and 2996 (family II). Thus the substitution created an extensive 2996-like area on the surface of the MC58 polypeptide, which could explain why chimeras including this substitution could elicit a bactericidal response against family II strains.

Substitution at the third underlined region (ProAsn instead of AlaGly) likely altered the local backbone conformation, introducing a high degree of rigidity which altered folding of the polypeptide and reduced bactericidal activity.

Based on a comparison of (i) sequence alignments within family II, and (ii) intra-family serum cross-reactivity, a number of amino acid residues were identified that could improve the ability of a chimera to elicit a good anti-II response. These residues are: (a) surface-exposed, based on the NMR structure, and so are immunoaccessible; (b) conserved within family II strains that were not killed by anti-2996 sera; and (c) not in the protein's hydrophobic pocket. Numbered according to SEQ ID NO:2, these residues were: D121; D165; A180; G181; K183; T185; T187; A191; A192; H196; K198; A213; S234; and G261. Except for D121 and D165, each of these residues was conserved in three strains which were resistant to antisera raised against the 2996 sequence. D121 is N in one of the three strains, and D165 is Sin two of the three strains.

Thus SEQ ID NO:57 was altered to give SEQ ID NO: 60, which was present as part of a full-length NMB1870 sequence.

The KLPEGGR 7-mer sequence (SEQ ID NO:61) in SEQ ID NO: 57 was replaced with the QLPDGK 6-mer (SEQ ID NO:62). Thus one amino acid is deleted. Depending on how these two sequences are aligned then the deleted residue can be identified as E51, G52, G53 or R54. The end result does not depend on which residue is nominally said to be deleted but, based on the alignment in reference 4, the deleted residue is best described as E51.

Tandem Polypeptides

As described in reference 12, a triple-tandem of all three NMB1870 families was prepared with the three families ordered I-III-II, from N-terminus to C-terminus. With or without a C-terminal histidine tag, this polypeptide elicited immune responses that were excellent against meningococci having a NMB1870 in families I and III (serum bactericidal titres ≧1:128 were typically seen against 100% of tested strains), but responses were weaker against strains in NMB1870 family II (≧1:128 titres typically seen against 60% of tested strains). In particular, responses were lower when using the tandem polypeptide than when using a mixture of the three separate proteins. In contrast, a II-III tandem gave good results, so the family II sequence is not inherently incompatible with the tandem expression approach.

Responses against families I and II are important, but family III strains are relatively rare. To improve efficacy against family II strains, three approaches have now been used: (a) the order of families was altered, to be I-II-III, II-III-I or II-I-III; (b) family III sequence was omitted, and families I and II were expressed either as I-II or as II-I; or (c) families I and II were expressed downstream of a ‘protein 936 sequence’, either as 936-I-II or as 936-II-I. These polypeptides were expressed with various linkers, leaders, etc., and with/without a C-terminal poly-His tag.

Embodiments of these three approaches are given as SEQ ID NOS: 27 to 38:

SEQ ID Description 27 II-I-His₆ 28 936-I-II-His₆ 29 936-II-I-His₆ 30 II-I-III-His₆ 31 II-III-I-His₆ 32 I-II-III-His₆ 33 II-I 34 936-I-II 35 936-II-I 36 II-III-I 37 II-I-III 38 I-II-III

These proteins were used to immunise mice. Different adjuvants were tested, including Freund's complete adjuvant, an aluminium hydroxide adjuvant, MF59 oil-in-water emulsion, and a mixture of MF59 and an immunostimulatory oligonucleotide. Mice's sera were tested in bactericidal assays.

In general, SEQ ID NOs: 28 and 29 were equally effective. SEQ ID NO: 34 sometimes showed better activity than SEQ ID NO: 28. For the proteins including all three families, the best results were generally seen with SEQ ID NO: 37.

Family II Sequences

5 different strains in NMB1870 family II were selected: M3153, M00-0243143; 1000, NGH38 and M0579. The following primers were used to amplify fragments for inserting into the NdeI/XhoI sites of a pET E. coli expression vector. The sequences were amplified as ΔG sequences; in the “chimΔG” sequences, the primer added SEQ ID NO: 66 to the N-terminus. Forward primers provided a NdeI site; reverse primers provided a XhoI site.

SEQ ID NO: STRAIN Fwd Rev M3153 ΔG741 67 68 chimΔG741 69 70 M00-0243143 ΔG741 71 72 chimΔG741 73 74 1000 ΔG741 75 76 chimΔG741 77 78 NGH38 ΔG741 79 80 chimΔG741 81 82 M0579 ΔG741 83 84 chimΔG741 85

New NMB1870 Sequences

Extensive sequence information for NMB1870 is available [e.g. refs 4, 7, 8 and 10]. Further new NMB1870 sequences have been found. These sequences are SEQ ID NOs: 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 63, 64, 65, 86, 87, 88, 89, 90, 91, 92, 93 and 94.

Sera raised against different NMB1870 proteins were tested against strain NM117. Bactericidal activity was lower for sera raised against proteins in families I, II or III than for the homologous serum. Similarly, sera raised against the NM117 sequence had relatively low SBA activity against strains in NMB1870 families I, II or III.

It will be understood that the invention is described above by way of example only and modifications may be made whilst remaining within the scope and spirit of the invention.

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BRIEF DESCRIPTION OF THE SEQUENCE LISTING

SEQ ID NO: Description 1 NMB1870 from strain MC58-family I 2 NMB1870 from strains 961-5945 & 2996-family II 3 NMB1870 from strain M1239-family III 4-6 Domains A to C from SEQ ID NO: 1 7-9 Domains A to C from SEQ ID NO: 2 10-12 Domains A to C from SEQ ID NO: 3 13 mature domain A from SEQ ID NO: 4 14 Protein 936 15-21 Linkers, etc. 22-24 ΔG versions of SEQ ID NOs: 1, 2 & 3 25 Truncated SEQ ID NO: 14 26 Linker 27-40 Hybrids & tandems 41-45 Linkers, etc. 46-56 Polymorphic forms of NMB1870 57 Reference sequence for substitutions 58-60 Chimeric sequences 61-62 Sequences swapped in SEQ ID NO: 57 63-65 NMB1870 from various strains 66 Linker 67-85 Primers 86-94 NMB1870 from various strains 95 ΔG form of NMNB1870 from strain nm 117 

1. A polypeptide comprising an amino acid sequence that has at least 70% identity to SEQ ID NO:57, and wherein one or more of the following residues is either substituted with another amino acid or is deleted: F14; T16; Q18; Q20; D21; S22; E23; H24; S25; G26; K27; K31; Q33; R35; 136; G37; 139; K48; E51; G52; R54; T56; A67; G68; K70; T72; A78; A79; N83; K85; D97; D102; P105; G107; R 109; S114; S116; L118; N120; Q121; A122; K135; T147; V148; N149; G150; I151; R152; H153.
 2. The polypeptide of claim 1, wherein at least one of the following residues is substituted or deleted: F14; T16; Q18; Q20; D21; S22; E23; H24; S25; G26; K27; K31; Q33; R35; 136; G37; K48; E51; G52; R54; T72; A79; K85; P105; G107; R109; L I 18; N120; Q121; A122; T147; V148; N149; G150: 1151; R152; H153.
 3. The polypeptide of claim 2, wherein E51 is deleted.
 4. The polypeptide of claim 1, wherein at least one of the following residues is substituted: F 14; T16; Q18; K31; Q33; R35; 136; G37; 139; T56; K70; T72; A78; A79; K85; D97; D102; SI 14; S116; L118; K135.
 5. The polypeptide of claim 2 or claim 4, comprising a substitution selected from: F14L; T161; Q18K; Q2ON; D21N; S22P; E23D; H24K; S251; S25T; G26D; K27S; K31Q; Q33S; R35L; 136V; G37S; I39L; K48Q; G52D; R54K; T56E; A67P; G68N; K70R; T72H; A78T; A79K; N83H; N83Y; K85R; D97E; D102E; P105A; G107E; R109S; S114L; S116D; L118R; N120G; Q121S; A122E; K135R; T1471; V148G; N149E; G150K; I151V; R152H; H153E.
 6. The polypeptide of claim 1, wherein the amino acid sequence has at least 80% identity to SEQ ID NO:57.
 7. The polypeptide of claim 1, wherein the amino acid sequence has at least 90% identity to SEQ ID NO:57.
 8. The polypeptide of claim 1, comprising an amino acid sequence selected from SEQ ID NO:58, SEQ ID NO:59 or SEQ ID NO.60.
 9. A polypeptide comprising a modified amino acid sequence of a first family of NMB 1870, wherein the modified sequence includes at least one (e.g. 1, 2, 3, 4, 5, 6 or 7) surface loop sequence from a second family of NMB 1870 in place of a surface loop sequence from the first family.
 10. A polypeptide comprising an amino acid sequence: —B1-L1-B2-L2-B3-L3-B4-L4-B5-L5-B6-L6-B7-L7-B8-L8-B9— wherein: (a) each of said B1, B2, B3, B4, B5, B6, B7, B8 and B9 is: (i) a fragment of SEQ ID NO: M; or (ii) an amino acid sequence having at least 75% sequence identity to said fragment of (i) and/or comprising a fragment of at least 10 contiguous amino acids from said fragment of (0; and (b) each of said L1, L2, L3, L4, L5, L6, L7 and L8 is: (i) a fragment of SEQ ID NO: 1, SEQ ID NO: 2 and/or of SEQ ID NO: 3; or (ii) an amino acid sequence having at least 75% sequence identity to said fragment of (i) and/or comprising a fragment of at least 10 contiguous amino acids from said fragment of (i), provided that at least one of said L1, L2, L3, L4, L5, L6, L7 and L8 is not a fragment of SEQ ID NO: M, wherein M is 1, 2 or 3, and B1, B2, B3, B4, B5, B6, B7, B8, B9, L1, L2, L3, L4, L5, L6, L7, L8 are selected as follows depending on M:
 11. A fragment of the polypeptide of claim 10, provided that the fragment includes at least one of L1, L2, L3, L4, L5, L6, L7 and/or L8 and at least one amino acid from two or more of B1, B2, B3, B4, B5, B6, B7, B8 and/or B9.
 12. A polypeptide comprising the chimeric amino acid sequence: —B1-L1-B2-L2-B3-L3-B4 L4-B5-L5-B6-L6-B7-L7-B8-L8-B9— as defined in claim 10 or claim 11 and further comprising, either N-terminal to or C-terminal to said chimeric sequence, a NMB 1870 sequence, wherein said NMB 1870 sequence is in the same NMB 1870 family as SEQ ID NO: M.
 13. A hybrid polypeptide of formula: wherein: X is an amino acid sequence comprising a Neisserial sequence, L is an optional linker amino acid sequence, A is an optional terminal amino acid sequence, B is an optional C terminal amino acid sequence, and n is 2 or more, wherein at least one of the —X— moieties is a NMB 1870 sequence.
 14. The hybrid polypeptide of claim 13, comprising an amino acid sequence selected from SEQ ID NOs: 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 and
 40. 15. The hybrid polypeptide of claim 13, wherein at least one of the —X— moieties has at least 90% sequence identity to SEQ ID NO:
 95. 16. A polypeptide comprising an amino acid sequence selected from SEQ ID NOs: 46, 47, 48, 49,50, 51, 52, 53, 54, 55, 56, 86, 87, 88, 89, 90, 91, 92, 93 and
 94. 